Some DRM drivers check the vgacon_text_force() function return value as an
indication on whether they should be allowed to be enabled or not.
This function returns true if the nomodeset kernel command line parameter
was set. But there may be other conditions besides this to determine if a
driver should be enabled.
Let's add a drm_drv_enabled() helper function to encapsulate that logic so
can be later extended if needed, without having to modify all the drivers.
Also, while being there do some cleanup. The vgacon_text_force() function
is guarded by CONFIG_VGA_CONSOLE and there's no need for callers to do it.
Suggested-by: Thomas Zimmermann <[email protected]>
Signed-off-by: Javier Martinez Canillas <[email protected]>
---
Changes in v2:
- Squash patch to add drm_drv_enabled() and make drivers use it.
- Make the drivers changes before moving nomodeset logic to DRM.
- Make drm_drv_enabled() return an errno and -ENODEV if nomodeset.
- Remove debug and error messages in drivers.
drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c | 7 +++----
drivers/gpu/drm/ast/ast_drv.c | 7 +++++--
drivers/gpu/drm/drm_drv.c | 20 ++++++++++++++++++++
drivers/gpu/drm/i915/i915_module.c | 6 +++++-
drivers/gpu/drm/mgag200/mgag200_drv.c | 7 +++++--
drivers/gpu/drm/nouveau/nouveau_drm.c | 5 ++++-
drivers/gpu/drm/qxl/qxl_drv.c | 7 +++++--
drivers/gpu/drm/radeon/radeon_drv.c | 6 ++++--
drivers/gpu/drm/tiny/bochs.c | 7 +++++--
drivers/gpu/drm/tiny/cirrus.c | 8 ++++++--
drivers/gpu/drm/vboxvideo/vbox_drv.c | 9 +++++----
drivers/gpu/drm/virtio/virtgpu_drv.c | 5 +++--
drivers/gpu/drm/vmwgfx/vmwgfx_drv.c | 5 +++--
include/drm/drm_drv.h | 1 +
14 files changed, 74 insertions(+), 26 deletions(-)
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
index c718fb5f3f8a..7fde40d06181 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
@@ -2514,10 +2514,9 @@ static int __init amdgpu_init(void)
{
int r;
- if (vgacon_text_force()) {
- DRM_ERROR("VGACON disables amdgpu kernel modesetting.\n");
- return -EINVAL;
- }
+ r = drm_drv_enabled(&amdgpu_kms_driver)
+ if (r)
+ return r;
r = amdgpu_sync_init();
if (r)
diff --git a/drivers/gpu/drm/ast/ast_drv.c b/drivers/gpu/drm/ast/ast_drv.c
index 86d5cd7b6318..802063279b86 100644
--- a/drivers/gpu/drm/ast/ast_drv.c
+++ b/drivers/gpu/drm/ast/ast_drv.c
@@ -233,8 +233,11 @@ static struct pci_driver ast_pci_driver = {
static int __init ast_init(void)
{
- if (vgacon_text_force() && ast_modeset == -1)
- return -EINVAL;
+ int ret;
+
+ ret = drm_drv_enabled(&ast_driver);
+ if (ret && ast_modeset == -1)
+ return ret;
if (ast_modeset == 0)
return -EINVAL;
diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c
index 8214a0b1ab7f..3fb567d62881 100644
--- a/drivers/gpu/drm/drm_drv.c
+++ b/drivers/gpu/drm/drm_drv.c
@@ -975,6 +975,26 @@ int drm_dev_set_unique(struct drm_device *dev, const char *name)
}
EXPORT_SYMBOL(drm_dev_set_unique);
+/**
+ * drm_drv_enabled - Checks if a DRM driver can be enabled
+ * @driver: DRM driver to check
+ *
+ * Checks whether a DRM driver can be enabled or not. This may be the case
+ * if the "nomodeset" kernel command line parameter is used.
+ *
+ * Return: 0 on success or a negative error code on failure.
+ */
+int drm_drv_enabled(const struct drm_driver *driver)
+{
+ if (vgacon_text_force()) {
+ DRM_INFO("%s driver is disabled\n", driver->name);
+ return -ENODEV;
+ }
+
+ return 0;
+}
+EXPORT_SYMBOL(drm_drv_enabled);
+
/*
* DRM Core
* The DRM core module initializes all global DRM objects and makes them
diff --git a/drivers/gpu/drm/i915/i915_module.c b/drivers/gpu/drm/i915/i915_module.c
index ab2295dd4500..45cb3e540eff 100644
--- a/drivers/gpu/drm/i915/i915_module.c
+++ b/drivers/gpu/drm/i915/i915_module.c
@@ -18,9 +18,12 @@
#include "i915_selftest.h"
#include "i915_vma.h"
+static const struct drm_driver driver;
+
static int i915_check_nomodeset(void)
{
bool use_kms = true;
+ int ret;
/*
* Enable KMS by default, unless explicitly overriden by
@@ -31,7 +34,8 @@ static int i915_check_nomodeset(void)
if (i915_modparams.modeset == 0)
use_kms = false;
- if (vgacon_text_force() && i915_modparams.modeset == -1)
+ ret = drm_drv_enabled(&driver);
+ if (ret && i915_modparams.modeset == -1)
use_kms = false;
if (!use_kms) {
diff --git a/drivers/gpu/drm/mgag200/mgag200_drv.c b/drivers/gpu/drm/mgag200/mgag200_drv.c
index 6b9243713b3c..2a581094ba2b 100644
--- a/drivers/gpu/drm/mgag200/mgag200_drv.c
+++ b/drivers/gpu/drm/mgag200/mgag200_drv.c
@@ -378,8 +378,11 @@ static struct pci_driver mgag200_pci_driver = {
static int __init mgag200_init(void)
{
- if (vgacon_text_force() && mgag200_modeset == -1)
- return -EINVAL;
+ int ret;
+
+ ret = drm_drv_enabled(&mgag200_driver);
+ if (ret && mgag200_modeset == -1)
+ return ret;
if (mgag200_modeset == 0)
return -EINVAL;
diff --git a/drivers/gpu/drm/nouveau/nouveau_drm.c b/drivers/gpu/drm/nouveau/nouveau_drm.c
index 1f828c9f691c..8844d3602d87 100644
--- a/drivers/gpu/drm/nouveau/nouveau_drm.c
+++ b/drivers/gpu/drm/nouveau/nouveau_drm.c
@@ -1316,13 +1316,16 @@ nouveau_platform_device_create(const struct nvkm_device_tegra_func *func,
static int __init
nouveau_drm_init(void)
{
+ int ret;
+
driver_pci = driver_stub;
driver_platform = driver_stub;
nouveau_display_options();
if (nouveau_modeset == -1) {
- if (vgacon_text_force())
+ ret = drm_drv_enabled(&driver_stub);
+ if (ret)
nouveau_modeset = 0;
}
diff --git a/drivers/gpu/drm/qxl/qxl_drv.c b/drivers/gpu/drm/qxl/qxl_drv.c
index fc47b0deb021..3ac2ef2bf545 100644
--- a/drivers/gpu/drm/qxl/qxl_drv.c
+++ b/drivers/gpu/drm/qxl/qxl_drv.c
@@ -295,8 +295,11 @@ static struct drm_driver qxl_driver = {
static int __init qxl_init(void)
{
- if (vgacon_text_force() && qxl_modeset == -1)
- return -EINVAL;
+ int ret;
+
+ ret = drm_drv_enabled(&qxl_driver);
+ if (ret && qxl_modeset == -1)
+ return ret;
if (qxl_modeset == 0)
return -EINVAL;
diff --git a/drivers/gpu/drm/radeon/radeon_drv.c b/drivers/gpu/drm/radeon/radeon_drv.c
index b74cebca1f89..56d688c04346 100644
--- a/drivers/gpu/drm/radeon/radeon_drv.c
+++ b/drivers/gpu/drm/radeon/radeon_drv.c
@@ -637,8 +637,10 @@ static struct pci_driver radeon_kms_pci_driver = {
static int __init radeon_module_init(void)
{
- if (vgacon_text_force() && radeon_modeset == -1) {
- DRM_INFO("VGACON disable radeon kernel modesetting.\n");
+ int ret;
+
+ ret = drm_drv_enabled(&kms_driver)
+ if (ret && radeon_modeset == -1) {
radeon_modeset = 0;
}
diff --git a/drivers/gpu/drm/tiny/bochs.c b/drivers/gpu/drm/tiny/bochs.c
index 2ce3bd903b70..ee6b1ff9128b 100644
--- a/drivers/gpu/drm/tiny/bochs.c
+++ b/drivers/gpu/drm/tiny/bochs.c
@@ -719,8 +719,11 @@ static struct pci_driver bochs_pci_driver = {
static int __init bochs_init(void)
{
- if (vgacon_text_force() && bochs_modeset == -1)
- return -EINVAL;
+ int ret;
+
+ ret = drm_drv_enabled(&bochs_driver);
+ if (ret && bochs_modeset == -1)
+ return ret;
if (bochs_modeset == 0)
return -EINVAL;
diff --git a/drivers/gpu/drm/tiny/cirrus.c b/drivers/gpu/drm/tiny/cirrus.c
index 4611ec408506..4706c5bc3067 100644
--- a/drivers/gpu/drm/tiny/cirrus.c
+++ b/drivers/gpu/drm/tiny/cirrus.c
@@ -636,8 +636,12 @@ static struct pci_driver cirrus_pci_driver = {
static int __init cirrus_init(void)
{
- if (vgacon_text_force())
- return -EINVAL;
+ int ret;
+
+ ret = drm_drv_enabled(&cirrus_driver);
+ if (ret)
+ return ret;
+
return pci_register_driver(&cirrus_pci_driver);
}
diff --git a/drivers/gpu/drm/vboxvideo/vbox_drv.c b/drivers/gpu/drm/vboxvideo/vbox_drv.c
index a6c81af37345..e4377c37cf33 100644
--- a/drivers/gpu/drm/vboxvideo/vbox_drv.c
+++ b/drivers/gpu/drm/vboxvideo/vbox_drv.c
@@ -193,10 +193,11 @@ static const struct drm_driver driver = {
static int __init vbox_init(void)
{
-#ifdef CONFIG_VGA_CONSOLE
- if (vgacon_text_force() && vbox_modeset == -1)
- return -EINVAL;
-#endif
+ int ret;
+
+ ret = drm_drv_enabled(&driver);
+ if (ret && vbox_modeset == -1)
+ return ret;
if (vbox_modeset == 0)
return -EINVAL;
diff --git a/drivers/gpu/drm/virtio/virtgpu_drv.c b/drivers/gpu/drm/virtio/virtgpu_drv.c
index 749db18dcfa2..28200dfba2d1 100644
--- a/drivers/gpu/drm/virtio/virtgpu_drv.c
+++ b/drivers/gpu/drm/virtio/virtgpu_drv.c
@@ -104,8 +104,9 @@ static int virtio_gpu_probe(struct virtio_device *vdev)
struct drm_device *dev;
int ret;
- if (vgacon_text_force() && virtio_gpu_modeset == -1)
- return -EINVAL;
+ ret = drm_drv_enabled(&driver);
+ if (ret && virtio_gpu_modeset == -1)
+ return ret;
if (virtio_gpu_modeset == 0)
return -EINVAL;
diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_drv.c b/drivers/gpu/drm/vmwgfx/vmwgfx_drv.c
index ab9a1750e1df..05e9949293d5 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_drv.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_drv.c
@@ -1651,8 +1651,9 @@ static int __init vmwgfx_init(void)
{
int ret;
- if (vgacon_text_force())
- return -EINVAL;
+ ret = drm_drv_enabled(&driver);
+ if (ret)
+ return ret;
ret = pci_register_driver(&vmw_pci_driver);
if (ret)
diff --git a/include/drm/drm_drv.h b/include/drm/drm_drv.h
index 0cd95953cdf5..77abfc7e078b 100644
--- a/include/drm/drm_drv.h
+++ b/include/drm/drm_drv.h
@@ -598,5 +598,6 @@ static inline bool drm_drv_uses_atomic_modeset(struct drm_device *dev)
int drm_dev_set_unique(struct drm_device *dev, const char *name);
+int drm_drv_enabled(const struct drm_driver *driver);
#endif
--
2.33.1
On Thu, 04 Nov 2021, Javier Martinez Canillas <[email protected]> wrote:
> Some DRM drivers check the vgacon_text_force() function return value as an
> indication on whether they should be allowed to be enabled or not.
>
> This function returns true if the nomodeset kernel command line parameter
> was set. But there may be other conditions besides this to determine if a
> driver should be enabled.
>
> Let's add a drm_drv_enabled() helper function to encapsulate that logic so
> can be later extended if needed, without having to modify all the drivers.
>
> Also, while being there do some cleanup. The vgacon_text_force() function
> is guarded by CONFIG_VGA_CONSOLE and there's no need for callers to do it.
>
> Suggested-by: Thomas Zimmermann <[email protected]>
> Signed-off-by: Javier Martinez Canillas <[email protected]>
> ---
>
> Changes in v2:
> - Squash patch to add drm_drv_enabled() and make drivers use it.
> - Make the drivers changes before moving nomodeset logic to DRM.
> - Make drm_drv_enabled() return an errno and -ENODEV if nomodeset.
> - Remove debug and error messages in drivers.
>
> drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c | 7 +++----
> drivers/gpu/drm/ast/ast_drv.c | 7 +++++--
> drivers/gpu/drm/drm_drv.c | 20 ++++++++++++++++++++
> drivers/gpu/drm/i915/i915_module.c | 6 +++++-
> drivers/gpu/drm/mgag200/mgag200_drv.c | 7 +++++--
> drivers/gpu/drm/nouveau/nouveau_drm.c | 5 ++++-
> drivers/gpu/drm/qxl/qxl_drv.c | 7 +++++--
> drivers/gpu/drm/radeon/radeon_drv.c | 6 ++++--
> drivers/gpu/drm/tiny/bochs.c | 7 +++++--
> drivers/gpu/drm/tiny/cirrus.c | 8 ++++++--
> drivers/gpu/drm/vboxvideo/vbox_drv.c | 9 +++++----
> drivers/gpu/drm/virtio/virtgpu_drv.c | 5 +++--
> drivers/gpu/drm/vmwgfx/vmwgfx_drv.c | 5 +++--
> include/drm/drm_drv.h | 1 +
> 14 files changed, 74 insertions(+), 26 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
> index c718fb5f3f8a..7fde40d06181 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
> @@ -2514,10 +2514,9 @@ static int __init amdgpu_init(void)
> {
> int r;
>
> - if (vgacon_text_force()) {
> - DRM_ERROR("VGACON disables amdgpu kernel modesetting.\n");
> - return -EINVAL;
> - }
> + r = drm_drv_enabled(&amdgpu_kms_driver)
> + if (r)
> + return r;
>
> r = amdgpu_sync_init();
> if (r)
> diff --git a/drivers/gpu/drm/ast/ast_drv.c b/drivers/gpu/drm/ast/ast_drv.c
> index 86d5cd7b6318..802063279b86 100644
> --- a/drivers/gpu/drm/ast/ast_drv.c
> +++ b/drivers/gpu/drm/ast/ast_drv.c
> @@ -233,8 +233,11 @@ static struct pci_driver ast_pci_driver = {
>
> static int __init ast_init(void)
> {
> - if (vgacon_text_force() && ast_modeset == -1)
> - return -EINVAL;
> + int ret;
> +
> + ret = drm_drv_enabled(&ast_driver);
> + if (ret && ast_modeset == -1)
> + return ret;
>
> if (ast_modeset == 0)
> return -EINVAL;
> diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c
> index 8214a0b1ab7f..3fb567d62881 100644
> --- a/drivers/gpu/drm/drm_drv.c
> +++ b/drivers/gpu/drm/drm_drv.c
> @@ -975,6 +975,26 @@ int drm_dev_set_unique(struct drm_device *dev, const char *name)
> }
> EXPORT_SYMBOL(drm_dev_set_unique);
>
> +/**
> + * drm_drv_enabled - Checks if a DRM driver can be enabled
> + * @driver: DRM driver to check
> + *
> + * Checks whether a DRM driver can be enabled or not. This may be the case
> + * if the "nomodeset" kernel command line parameter is used.
> + *
> + * Return: 0 on success or a negative error code on failure.
> + */
> +int drm_drv_enabled(const struct drm_driver *driver)
> +{
> + if (vgacon_text_force()) {
> + DRM_INFO("%s driver is disabled\n", driver->name);
> + return -ENODEV;
> + }
> +
> + return 0;
> +}
> +EXPORT_SYMBOL(drm_drv_enabled);
> +
> /*
> * DRM Core
> * The DRM core module initializes all global DRM objects and makes them
> diff --git a/drivers/gpu/drm/i915/i915_module.c b/drivers/gpu/drm/i915/i915_module.c
> index ab2295dd4500..45cb3e540eff 100644
> --- a/drivers/gpu/drm/i915/i915_module.c
> +++ b/drivers/gpu/drm/i915/i915_module.c
> @@ -18,9 +18,12 @@
> #include "i915_selftest.h"
> #include "i915_vma.h"
>
> +static const struct drm_driver driver;
> +
No, this makes absolutely no sense, and will also oops on nomodeset.
BR,
Jani.
> static int i915_check_nomodeset(void)
> {
> bool use_kms = true;
> + int ret;
>
> /*
> * Enable KMS by default, unless explicitly overriden by
> @@ -31,7 +34,8 @@ static int i915_check_nomodeset(void)
> if (i915_modparams.modeset == 0)
> use_kms = false;
>
> - if (vgacon_text_force() && i915_modparams.modeset == -1)
> + ret = drm_drv_enabled(&driver);
> + if (ret && i915_modparams.modeset == -1)
> use_kms = false;
>
> if (!use_kms) {
> diff --git a/drivers/gpu/drm/mgag200/mgag200_drv.c b/drivers/gpu/drm/mgag200/mgag200_drv.c
> index 6b9243713b3c..2a581094ba2b 100644
> --- a/drivers/gpu/drm/mgag200/mgag200_drv.c
> +++ b/drivers/gpu/drm/mgag200/mgag200_drv.c
> @@ -378,8 +378,11 @@ static struct pci_driver mgag200_pci_driver = {
>
> static int __init mgag200_init(void)
> {
> - if (vgacon_text_force() && mgag200_modeset == -1)
> - return -EINVAL;
> + int ret;
> +
> + ret = drm_drv_enabled(&mgag200_driver);
> + if (ret && mgag200_modeset == -1)
> + return ret;
>
> if (mgag200_modeset == 0)
> return -EINVAL;
> diff --git a/drivers/gpu/drm/nouveau/nouveau_drm.c b/drivers/gpu/drm/nouveau/nouveau_drm.c
> index 1f828c9f691c..8844d3602d87 100644
> --- a/drivers/gpu/drm/nouveau/nouveau_drm.c
> +++ b/drivers/gpu/drm/nouveau/nouveau_drm.c
> @@ -1316,13 +1316,16 @@ nouveau_platform_device_create(const struct nvkm_device_tegra_func *func,
> static int __init
> nouveau_drm_init(void)
> {
> + int ret;
> +
> driver_pci = driver_stub;
> driver_platform = driver_stub;
>
> nouveau_display_options();
>
> if (nouveau_modeset == -1) {
> - if (vgacon_text_force())
> + ret = drm_drv_enabled(&driver_stub);
> + if (ret)
> nouveau_modeset = 0;
> }
>
> diff --git a/drivers/gpu/drm/qxl/qxl_drv.c b/drivers/gpu/drm/qxl/qxl_drv.c
> index fc47b0deb021..3ac2ef2bf545 100644
> --- a/drivers/gpu/drm/qxl/qxl_drv.c
> +++ b/drivers/gpu/drm/qxl/qxl_drv.c
> @@ -295,8 +295,11 @@ static struct drm_driver qxl_driver = {
>
> static int __init qxl_init(void)
> {
> - if (vgacon_text_force() && qxl_modeset == -1)
> - return -EINVAL;
> + int ret;
> +
> + ret = drm_drv_enabled(&qxl_driver);
> + if (ret && qxl_modeset == -1)
> + return ret;
>
> if (qxl_modeset == 0)
> return -EINVAL;
> diff --git a/drivers/gpu/drm/radeon/radeon_drv.c b/drivers/gpu/drm/radeon/radeon_drv.c
> index b74cebca1f89..56d688c04346 100644
> --- a/drivers/gpu/drm/radeon/radeon_drv.c
> +++ b/drivers/gpu/drm/radeon/radeon_drv.c
> @@ -637,8 +637,10 @@ static struct pci_driver radeon_kms_pci_driver = {
>
> static int __init radeon_module_init(void)
> {
> - if (vgacon_text_force() && radeon_modeset == -1) {
> - DRM_INFO("VGACON disable radeon kernel modesetting.\n");
> + int ret;
> +
> + ret = drm_drv_enabled(&kms_driver)
> + if (ret && radeon_modeset == -1) {
> radeon_modeset = 0;
> }
>
> diff --git a/drivers/gpu/drm/tiny/bochs.c b/drivers/gpu/drm/tiny/bochs.c
> index 2ce3bd903b70..ee6b1ff9128b 100644
> --- a/drivers/gpu/drm/tiny/bochs.c
> +++ b/drivers/gpu/drm/tiny/bochs.c
> @@ -719,8 +719,11 @@ static struct pci_driver bochs_pci_driver = {
>
> static int __init bochs_init(void)
> {
> - if (vgacon_text_force() && bochs_modeset == -1)
> - return -EINVAL;
> + int ret;
> +
> + ret = drm_drv_enabled(&bochs_driver);
> + if (ret && bochs_modeset == -1)
> + return ret;
>
> if (bochs_modeset == 0)
> return -EINVAL;
> diff --git a/drivers/gpu/drm/tiny/cirrus.c b/drivers/gpu/drm/tiny/cirrus.c
> index 4611ec408506..4706c5bc3067 100644
> --- a/drivers/gpu/drm/tiny/cirrus.c
> +++ b/drivers/gpu/drm/tiny/cirrus.c
> @@ -636,8 +636,12 @@ static struct pci_driver cirrus_pci_driver = {
>
> static int __init cirrus_init(void)
> {
> - if (vgacon_text_force())
> - return -EINVAL;
> + int ret;
> +
> + ret = drm_drv_enabled(&cirrus_driver);
> + if (ret)
> + return ret;
> +
> return pci_register_driver(&cirrus_pci_driver);
> }
>
> diff --git a/drivers/gpu/drm/vboxvideo/vbox_drv.c b/drivers/gpu/drm/vboxvideo/vbox_drv.c
> index a6c81af37345..e4377c37cf33 100644
> --- a/drivers/gpu/drm/vboxvideo/vbox_drv.c
> +++ b/drivers/gpu/drm/vboxvideo/vbox_drv.c
> @@ -193,10 +193,11 @@ static const struct drm_driver driver = {
>
> static int __init vbox_init(void)
> {
> -#ifdef CONFIG_VGA_CONSOLE
> - if (vgacon_text_force() && vbox_modeset == -1)
> - return -EINVAL;
> -#endif
> + int ret;
> +
> + ret = drm_drv_enabled(&driver);
> + if (ret && vbox_modeset == -1)
> + return ret;
>
> if (vbox_modeset == 0)
> return -EINVAL;
> diff --git a/drivers/gpu/drm/virtio/virtgpu_drv.c b/drivers/gpu/drm/virtio/virtgpu_drv.c
> index 749db18dcfa2..28200dfba2d1 100644
> --- a/drivers/gpu/drm/virtio/virtgpu_drv.c
> +++ b/drivers/gpu/drm/virtio/virtgpu_drv.c
> @@ -104,8 +104,9 @@ static int virtio_gpu_probe(struct virtio_device *vdev)
> struct drm_device *dev;
> int ret;
>
> - if (vgacon_text_force() && virtio_gpu_modeset == -1)
> - return -EINVAL;
> + ret = drm_drv_enabled(&driver);
> + if (ret && virtio_gpu_modeset == -1)
> + return ret;
>
> if (virtio_gpu_modeset == 0)
> return -EINVAL;
> diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_drv.c b/drivers/gpu/drm/vmwgfx/vmwgfx_drv.c
> index ab9a1750e1df..05e9949293d5 100644
> --- a/drivers/gpu/drm/vmwgfx/vmwgfx_drv.c
> +++ b/drivers/gpu/drm/vmwgfx/vmwgfx_drv.c
> @@ -1651,8 +1651,9 @@ static int __init vmwgfx_init(void)
> {
> int ret;
>
> - if (vgacon_text_force())
> - return -EINVAL;
> + ret = drm_drv_enabled(&driver);
> + if (ret)
> + return ret;
>
> ret = pci_register_driver(&vmw_pci_driver);
> if (ret)
> diff --git a/include/drm/drm_drv.h b/include/drm/drm_drv.h
> index 0cd95953cdf5..77abfc7e078b 100644
> --- a/include/drm/drm_drv.h
> +++ b/include/drm/drm_drv.h
> @@ -598,5 +598,6 @@ static inline bool drm_drv_uses_atomic_modeset(struct drm_device *dev)
>
> int drm_dev_set_unique(struct drm_device *dev, const char *name);
>
> +int drm_drv_enabled(const struct drm_driver *driver);
>
> #endif
--
Jani Nikula, Intel Open Source Graphics Center
On 11/4/21 17:24, Jani Nikula wrote:
[snip]
>> index ab2295dd4500..45cb3e540eff 100644
>> --- a/drivers/gpu/drm/i915/i915_module.c
>> +++ b/drivers/gpu/drm/i915/i915_module.c
>> @@ -18,9 +18,12 @@
>> #include "i915_selftest.h"
>> #include "i915_vma.h"
>>
>> +static const struct drm_driver driver;
>> +
>
> No, this makes absolutely no sense, and will also oops on nomodeset.
>
Ups, sorry about that. For some reason I thought that it was defined in
the same compilation unit, but I noticed now that it is in i915_drv.c.
> BR,
> Jani.
>
Best regards,
--
Javier Martinez Canillas
Linux Engineering
Red Hat
On Thu, 04 Nov 2021, Sam Ravnborg <[email protected]> wrote:
> Hi Javier,
>
> On Thu, Nov 04, 2021 at 05:07:06PM +0100, Javier Martinez Canillas wrote:
>> Some DRM drivers check the vgacon_text_force() function return value as an
>> indication on whether they should be allowed to be enabled or not.
>>
>> This function returns true if the nomodeset kernel command line parameter
>> was set. But there may be other conditions besides this to determine if a
>> driver should be enabled.
>>
>> Let's add a drm_drv_enabled() helper function to encapsulate that logic so
>> can be later extended if needed, without having to modify all the drivers.
>>
>> Also, while being there do some cleanup. The vgacon_text_force() function
>> is guarded by CONFIG_VGA_CONSOLE and there's no need for callers to do it.
>>
>> Suggested-by: Thomas Zimmermann <[email protected]>
>> Signed-off-by: Javier Martinez Canillas <[email protected]>
>> ---
>>
>> diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c
>> index 8214a0b1ab7f..3fb567d62881 100644
>> --- a/drivers/gpu/drm/drm_drv.c
>> +++ b/drivers/gpu/drm/drm_drv.c
>> @@ -975,6 +975,26 @@ int drm_dev_set_unique(struct drm_device *dev, const char *name)
>> }
>> EXPORT_SYMBOL(drm_dev_set_unique);
>>
>> +/**
>> + * drm_drv_enabled - Checks if a DRM driver can be enabled
>> + * @driver: DRM driver to check
>> + *
>> + * Checks whether a DRM driver can be enabled or not. This may be the case
>> + * if the "nomodeset" kernel command line parameter is used.
>> + *
>> + * Return: 0 on success or a negative error code on failure.
>> + */
>> +int drm_drv_enabled(const struct drm_driver *driver)
>> +{
>> + if (vgacon_text_force()) {
>> + DRM_INFO("%s driver is disabled\n", driver->name);
>
> DRM_INFO is deprecated, please do not use it in new code.
> Also other users had an error message and not just info - is info
> enough?
>
>
>> + return -ENODEV;
>> + }
>> +
>> + return 0;
>> +}
>> +EXPORT_SYMBOL(drm_drv_enabled);
>> +
>> /*
>> * DRM Core
>> * The DRM core module initializes all global DRM objects and makes them
>> diff --git a/drivers/gpu/drm/i915/i915_module.c b/drivers/gpu/drm/i915/i915_module.c
>> index ab2295dd4500..45cb3e540eff 100644
>> --- a/drivers/gpu/drm/i915/i915_module.c
>> +++ b/drivers/gpu/drm/i915/i915_module.c
>> @@ -18,9 +18,12 @@
>> #include "i915_selftest.h"
>> #include "i915_vma.h"
>>
>> +static const struct drm_driver driver;
> Hmmm...
>
>> +
>> static int i915_check_nomodeset(void)
>> {
>> bool use_kms = true;
>> + int ret;
>>
>> /*
>> * Enable KMS by default, unless explicitly overriden by
>> @@ -31,7 +34,8 @@ static int i915_check_nomodeset(void)
>> if (i915_modparams.modeset == 0)
>> use_kms = false;
>>
>> - if (vgacon_text_force() && i915_modparams.modeset == -1)
>> + ret = drm_drv_enabled(&driver);
>
> You pass the local driver variable here - which looks wrong as this is
> not the same as the driver variable declared in another file.
Indeed.
> Maybe move the check to new function you can add to init_funcs,
> and locate the new function in i915_drv - so it has access to driver?
We don't really want that, though. This check is pretty much as early as
it can be, and there's a ton of useless initialization that would happen
if we waited until drm_driver is available.
From my POV, drm_drv_enabled() is a solution that creates a worse
problem for us than it solves.
BR,
Jani.
>
>
> Sam
--
Jani Nikula, Intel Open Source Graphics Center
Hello Sam,
On 11/4/21 18:57, Jani Nikula wrote:
> On Thu, 04 Nov 2021, Sam Ravnborg <[email protected]> wrote:
>> Hi Javier,
>>
>> On Thu, Nov 04, 2021 at 05:07:06PM +0100, Javier Martinez Canillas wrote:
>>> Some DRM drivers check the vgacon_text_force() function return value as an
>>> indication on whether they should be allowed to be enabled or not.
>>>
>>> This function returns true if the nomodeset kernel command line parameter
>>> was set. But there may be other conditions besides this to determine if a
>>> driver should be enabled.
>>>
>>> Let's add a drm_drv_enabled() helper function to encapsulate that logic so
>>> can be later extended if needed, without having to modify all the drivers.
>>>
>>> Also, while being there do some cleanup. The vgacon_text_force() function
>>> is guarded by CONFIG_VGA_CONSOLE and there's no need for callers to do it.
>>>
>>> Suggested-by: Thomas Zimmermann <[email protected]>
>>> Signed-off-by: Javier Martinez Canillas <[email protected]>
>>> ---
>>>
>>> diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c
>>> index 8214a0b1ab7f..3fb567d62881 100644
>>> --- a/drivers/gpu/drm/drm_drv.c
>>> +++ b/drivers/gpu/drm/drm_drv.c
>>> @@ -975,6 +975,26 @@ int drm_dev_set_unique(struct drm_device *dev, const char *name)
>>> }
>>> EXPORT_SYMBOL(drm_dev_set_unique);
>>>
>>> +/**
>>> + * drm_drv_enabled - Checks if a DRM driver can be enabled
>>> + * @driver: DRM driver to check
>>> + *
>>> + * Checks whether a DRM driver can be enabled or not. This may be the case
>>> + * if the "nomodeset" kernel command line parameter is used.
>>> + *
>>> + * Return: 0 on success or a negative error code on failure.
>>> + */
>>> +int drm_drv_enabled(const struct drm_driver *driver)
>>> +{
>>> + if (vgacon_text_force()) {
>>> + DRM_INFO("%s driver is disabled\n", driver->name);
>>
>> DRM_INFO is deprecated, please do not use it in new code.
>> Also other users had an error message and not just info - is info
>> enough?
>>
Thanks, I didn't know that. Right, they had an error but I do wonder
if that was correct though. After all isn't an error but an explicit
disable due "nomodeset" being set in the kernel command line.
[snip]
>>>
>>> - if (vgacon_text_force() && i915_modparams.modeset == -1)
>>> + ret = drm_drv_enabled(&driver);
>>
>> You pass the local driver variable here - which looks wrong as this is
>> not the same as the driver variable declared in another file.
>
Yes, Jani mentioned it already. I got confused and thought that the driver
variable was also defined in the same compilation unit...
Maybe I could squash the following change?
diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
index b18a250e5d2e..b8f399b76363 100644
--- a/drivers/gpu/drm/i915/i915_drv.c
+++ b/drivers/gpu/drm/i915/i915_drv.c
@@ -89,7 +89,7 @@
#include "intel_region_ttm.h"
#include "vlv_suspend.h"
-static const struct drm_driver driver;
+const struct drm_driver driver;
static int i915_get_bridge_dev(struct drm_i915_private *dev_priv)
{
@@ -1777,7 +1777,7 @@ static const struct drm_ioctl_desc i915_ioctls[] = {
DRM_IOCTL_DEF_DRV(I915_GEM_VM_DESTROY, i915_gem_vm_destroy_ioctl, DRM_RENDER_ALLOW),
};
-static const struct drm_driver driver = {
+const struct drm_driver driver = {
/* Don't use MTRRs here; the Xserver or userspace app should
* deal with them for Intel hardware.
*/
diff --git a/drivers/gpu/drm/i915/i915_module.c b/drivers/gpu/drm/i915/i915_module.c
index c890c1ca20c4..88f770920324 100644
--- a/drivers/gpu/drm/i915/i915_module.c
+++ b/drivers/gpu/drm/i915/i915_module.c
@@ -16,7 +16,7 @@
#include "i915_selftest.h"
#include "i915_vma.h"
-static const struct drm_driver driver;
+extern const struct drm_driver driver;
static int i915_check_nomodeset(void)
{
That should work and I actually got a laptop with an i915 and tested the change
both when CONFIG_DRM_I915=m and CONFIG_DRM_I915=y is set.
Another option is to declare it in i915_drv.h and not make the definition static.
> Indeed.
>
>> Maybe move the check to new function you can add to init_funcs,
>> and locate the new function in i915_drv - so it has access to driver?
>
> We don't really want that, though. This check is pretty much as early as
> it can be, and there's a ton of useless initialization that would happen
> if we waited until drm_driver is available.
>
Agreed.
> From my POV, drm_drv_enabled() is a solution that creates a worse
> problem for us than it solves.
>
I don't have a strong opinion on this. I could just do patch #2 without adding
a level of indirection through drm_drv_enabled(). But Thomas and Daniel Vetter
suggested that we should do this change before.
That is, the drivers could just check if should be enabled by calling to the
drm_check_modeset() function directly if people agree that encapsulating that
logic in a drm_drv_enabled() is not needed.
>
> BR,
> Jani.
>
Best regards,
--
Javier Martinez Canillas
Linux Engineering
Red Hat
On Thu, 04 Nov 2021, Sam Ravnborg <[email protected]> wrote:
> Hi Javier,
>
>>
>> >>>
>> >>> - if (vgacon_text_force() && i915_modparams.modeset == -1)
>> >>> + ret = drm_drv_enabled(&driver);
>> >>
>> >> You pass the local driver variable here - which looks wrong as this is
>> >> not the same as the driver variable declared in another file.
>> >
>>
>> Yes, Jani mentioned it already. I got confused and thought that the driver
>> variable was also defined in the same compilation unit...
>>
>> Maybe I could squash the following change?
>>
>> diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
>> index b18a250e5d2e..b8f399b76363 100644
>> --- a/drivers/gpu/drm/i915/i915_drv.c
>> +++ b/drivers/gpu/drm/i915/i915_drv.c
>> @@ -89,7 +89,7 @@
>> #include "intel_region_ttm.h"
>> #include "vlv_suspend.h"
>>
>> -static const struct drm_driver driver;
>> +const struct drm_driver driver;
> No, variables with such a generic name will clash.
>
> Just add a
> const drm_driver * i915_drm_driver(void)
> {
> return &driver;
> }
>
> And then use this function to access the drm_driver variable.
Agreed on the general principle of exposing interfaces over data.
But... why? I'm still at a loss what problem this solves. We pass
&driver to exactly one place, devm_drm_dev_alloc(), and it's neatly
hidden away.
BR,
Jani.
--
Jani Nikula, Intel Open Source Graphics Center
On Thu, 04 Nov 2021, Javier Martinez Canillas <[email protected]> wrote:
> +/**
> + * drm_drv_enabled - Checks if a DRM driver can be enabled
> + * @driver: DRM driver to check
> + *
> + * Checks whether a DRM driver can be enabled or not. This may be the case
> + * if the "nomodeset" kernel command line parameter is used.
> + *
> + * Return: 0 on success or a negative error code on failure.
> + */
> +int drm_drv_enabled(const struct drm_driver *driver)
> +{
> + if (vgacon_text_force()) {
> + DRM_INFO("%s driver is disabled\n", driver->name);
> + return -ENODEV;
> + }
> +
> + return 0;
> +}
> +EXPORT_SYMBOL(drm_drv_enabled);
The name implies a bool return, but it's not.
if (drm_drv_enabled(...)) {
/* surprise, it's disabled! */
}
BR,
Jani.
--
Jani Nikula, Intel Open Source Graphics Center
Hello Jani,
On 11/4/21 20:57, Jani Nikula wrote:
> On Thu, 04 Nov 2021, Javier Martinez Canillas <[email protected]> wrote:
>> +/**
>> + * drm_drv_enabled - Checks if a DRM driver can be enabled
>> + * @driver: DRM driver to check
>> + *
>> + * Checks whether a DRM driver can be enabled or not. This may be the case
>> + * if the "nomodeset" kernel command line parameter is used.
>> + *
>> + * Return: 0 on success or a negative error code on failure.
>> + */
>> +int drm_drv_enabled(const struct drm_driver *driver)
>> +{
>> + if (vgacon_text_force()) {
>> + DRM_INFO("%s driver is disabled\n", driver->name);
>> + return -ENODEV;
>> + }
>> +
>> + return 0;
>> +}
>> +EXPORT_SYMBOL(drm_drv_enabled);
>
> The name implies a bool return, but it's not.
>
> if (drm_drv_enabled(...)) {
> /* surprise, it's disabled! */
> }
>
It used to return a bool in v2 but Thomas suggested an int instead to
have consistency on the errno code that was returned by the callers.
I should probably name that function differently to avoid confusion.
But I think you are correct and this change is caused too much churn
for not that much benefit, specially since is unclear that there might
be another condition to prevent a DRM driver to load besides nomodeset.
I'll just drop this patch and post only #2 but making drivers to test
using the drm_check_modeset() function (which doesn't have a name that
implies a bool return).
>
> BR,
> Jani.
>
>
>
Best regards,
--
Javier Martinez Canillas
Linux Engineering
Red Hat
Hi
Am 04.11.21 um 21:09 schrieb Javier Martinez Canillas:
> Hello Jani,
>
> On 11/4/21 20:57, Jani Nikula wrote:
>> On Thu, 04 Nov 2021, Javier Martinez Canillas <[email protected]> wrote:
>>> +/**
>>> + * drm_drv_enabled - Checks if a DRM driver can be enabled
>>> + * @driver: DRM driver to check
>>> + *
>>> + * Checks whether a DRM driver can be enabled or not. This may be the case
>>> + * if the "nomodeset" kernel command line parameter is used.
>>> + *
>>> + * Return: 0 on success or a negative error code on failure.
>>> + */
>>> +int drm_drv_enabled(const struct drm_driver *driver)
Jani mentioned that i915 absolutely wants this to run from the
module_init function. Best is to drop the parameter.
>>> +{
>>> + if (vgacon_text_force()) {
>>> + DRM_INFO("%s driver is disabled\n", driver->name);
>>> + return -ENODEV;
>>> + }
If we run this from within a module_init function, we'd get plenty of
these warnings if drivers are compiled into the kernel. Maybe simply
remove the message. There's already a warning printed by the nomodeset
handler.
>>> +
>>> + return 0;
>>> +}
>>> +EXPORT_SYMBOL(drm_drv_enabled);
>>
>> The name implies a bool return, but it's not.
>>
>> if (drm_drv_enabled(...)) {
>> /* surprise, it's disabled! */
>> }
>>
>
> It used to return a bool in v2 but Thomas suggested an int instead to
> have consistency on the errno code that was returned by the callers.
>
> I should probably name that function differently to avoid confusion.
Yes, please.
Best regards
Thomas
>
> But I think you are correct and this change is caused too much churn
> for not that much benefit, specially since is unclear that there might
> be another condition to prevent a DRM driver to load besides nomodeset.
>
> I'll just drop this patch and post only #2 but making drivers to test
> using the drm_check_modeset() function (which doesn't have a name that
> implies a bool return).
>
>>
>> BR,
>> Jani.
>>
>>
>>
>
> Best regards,
>
--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Maxfeldstr. 5, 90409 Nürnberg, Germany
(HRB 36809, AG Nürnberg)
Geschäftsführer: Ivo Totev
On Fri, 05 Nov 2021, Javier Martinez Canillas <[email protected]> wrote:
> Hello Thomas,
>
> On 11/5/21 09:43, Thomas Zimmermann wrote:
>> Hi
>>
>> Am 04.11.21 um 21:09 schrieb Javier Martinez Canillas:
>>> Hello Jani,
>>>
>>> On 11/4/21 20:57, Jani Nikula wrote:
>>>> On Thu, 04 Nov 2021, Javier Martinez Canillas <[email protected]> wrote:
>>>>> +/**
>>>>> + * drm_drv_enabled - Checks if a DRM driver can be enabled
>>>>> + * @driver: DRM driver to check
>>>>> + *
>>>>> + * Checks whether a DRM driver can be enabled or not. This may be the case
>>>>> + * if the "nomodeset" kernel command line parameter is used.
>>>>> + *
>>>>> + * Return: 0 on success or a negative error code on failure.
>>>>> + */
>>>>> +int drm_drv_enabled(const struct drm_driver *driver)
>>
>> Jani mentioned that i915 absolutely wants this to run from the
>> module_init function. Best is to drop the parameter.
>>
>
> Ok. I now wonder though how much value would add this function since
> it will just be a wrapper around the nomodeset check.
>
> We talked about adding a new DRIVER_GENERIC feature flag and check for
> this, but as danvet mentioned that is not really needed. We just need
> to avoid testing for nomodeset in the simpledrm driver.
>
> Do you envision other condition that could be added later to disable a
> DRM driver ? Or do you think that just from a code readability point of
> view makes worth it ?
Taking a step back for perspective.
I think there's broad consensus in moving the parameter to drm, naming
the check function to drm_something_something(), and breaking the ties
to CONFIG_VGA_CONSOLE. I appreciate the work you're doing to that
effect.
I think everything beyond that is still a bit vague and/or
contentious. So how about making the first 2-3 patches just that?
Something we can all agree on, makes good progress, improves the kernel,
and gives us something to build on?
BR,
Jani.
>
>>>>> +{
>>>>> + if (vgacon_text_force()) {
>>>>> + DRM_INFO("%s driver is disabled\n", driver->name);
>>>>> + return -ENODEV;
>>>>> + }
>>
>> If we run this from within a module_init function, we'd get plenty of
>> these warnings if drivers are compiled into the kernel. Maybe simply
>> remove the message. There's already a warning printed by the nomodeset
>> handler.
>>
>
> Indeed. I'll just drop it.
>
>>>>> +
>>>>> + return 0;
>>>>> +}
>>>>> +EXPORT_SYMBOL(drm_drv_enabled);
>>>>
>>>> The name implies a bool return, but it's not.
>>>>
>>>> if (drm_drv_enabled(...)) {
>>>> /* surprise, it's disabled! */
>>>> }
>>>>
>>>
>>> It used to return a bool in v2 but Thomas suggested an int instead to
>>> have consistency on the errno code that was returned by the callers.
>>>
>>> I should probably name that function differently to avoid confusion.
>>
>> Yes, please.
>>
>
> drm_driver_check() maybe ?
>
> Best regards,
--
Jani Nikula, Intel Open Source Graphics Center
Hi
Am 05.11.21 um 10:48 schrieb Javier Martinez Canillas:
> Hello Thomas,
>
> On 11/5/21 09:43, Thomas Zimmermann wrote:
>> Hi
>>
>> Am 04.11.21 um 21:09 schrieb Javier Martinez Canillas:
>>> Hello Jani,
>>>
>>> On 11/4/21 20:57, Jani Nikula wrote:
>>>> On Thu, 04 Nov 2021, Javier Martinez Canillas <[email protected]> wrote:
>>>>> +/**
>>>>> + * drm_drv_enabled - Checks if a DRM driver can be enabled
>>>>> + * @driver: DRM driver to check
>>>>> + *
>>>>> + * Checks whether a DRM driver can be enabled or not. This may be the case
>>>>> + * if the "nomodeset" kernel command line parameter is used.
>>>>> + *
>>>>> + * Return: 0 on success or a negative error code on failure.
>>>>> + */
>>>>> +int drm_drv_enabled(const struct drm_driver *driver)
>>
>> Jani mentioned that i915 absolutely wants this to run from the
>> module_init function. Best is to drop the parameter.
>>
>
> Ok. I now wonder though how much value would add this function since
> it will just be a wrapper around the nomodeset check.
>
> We talked about adding a new DRIVER_GENERIC feature flag and check for
> this, but as danvet mentioned that is not really needed. We just need
> to avoid testing for nomodeset in the simpledrm driver.
>
> Do you envision other condition that could be added later to disable a
> DRM driver ? Or do you think that just from a code readability point of
> view makes worth it ?
DRIVER_GENERIC would have been nice, but it's not happening now.
I suggest to move over the nomodeset parameter (i.e., this patchset),
then make the config option system agnostic, and finally add the test to
all drivers expect simpledrm. That should solve the imminent problem.
Best regards
Thomas
>
>>>>> +{
>>>>> + if (vgacon_text_force()) {
>>>>> + DRM_INFO("%s driver is disabled\n", driver->name);
>>>>> + return -ENODEV;
>>>>> + }
>>
>> If we run this from within a module_init function, we'd get plenty of
>> these warnings if drivers are compiled into the kernel. Maybe simply
>> remove the message. There's already a warning printed by the nomodeset
>> handler.
>>
>
> Indeed. I'll just drop it.
>
>>>>> +
>>>>> + return 0;
>>>>> +}
>>>>> +EXPORT_SYMBOL(drm_drv_enabled);
>>>>
>>>> The name implies a bool return, but it's not.
>>>>
>>>> if (drm_drv_enabled(...)) {
>>>> /* surprise, it's disabled! */
>>>> }
>>>>
>>>
>>> It used to return a bool in v2 but Thomas suggested an int instead to
>>> have consistency on the errno code that was returned by the callers.
>>>
>>> I should probably name that function differently to avoid confusion.
>>
>> Yes, please.
>>
>
> drm_driver_check() maybe ?
>
> Best regards,
>
--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Maxfeldstr. 5, 90409 Nürnberg, Germany
(HRB 36809, AG Nürnberg)
Geschäftsführer: Ivo Totev
Hello Thomas,
On 11/5/21 09:43, Thomas Zimmermann wrote:
> Hi
>
> Am 04.11.21 um 21:09 schrieb Javier Martinez Canillas:
>> Hello Jani,
>>
>> On 11/4/21 20:57, Jani Nikula wrote:
>>> On Thu, 04 Nov 2021, Javier Martinez Canillas <[email protected]> wrote:
>>>> +/**
>>>> + * drm_drv_enabled - Checks if a DRM driver can be enabled
>>>> + * @driver: DRM driver to check
>>>> + *
>>>> + * Checks whether a DRM driver can be enabled or not. This may be the case
>>>> + * if the "nomodeset" kernel command line parameter is used.
>>>> + *
>>>> + * Return: 0 on success or a negative error code on failure.
>>>> + */
>>>> +int drm_drv_enabled(const struct drm_driver *driver)
>
> Jani mentioned that i915 absolutely wants this to run from the
> module_init function. Best is to drop the parameter.
>
Ok. I now wonder though how much value would add this function since
it will just be a wrapper around the nomodeset check.
We talked about adding a new DRIVER_GENERIC feature flag and check for
this, but as danvet mentioned that is not really needed. We just need
to avoid testing for nomodeset in the simpledrm driver.
Do you envision other condition that could be added later to disable a
DRM driver ? Or do you think that just from a code readability point of
view makes worth it ?
>>>> +{
>>>> + if (vgacon_text_force()) {
>>>> + DRM_INFO("%s driver is disabled\n", driver->name);
>>>> + return -ENODEV;
>>>> + }
>
> If we run this from within a module_init function, we'd get plenty of
> these warnings if drivers are compiled into the kernel. Maybe simply
> remove the message. There's already a warning printed by the nomodeset
> handler.
>
Indeed. I'll just drop it.
>>>> +
>>>> + return 0;
>>>> +}
>>>> +EXPORT_SYMBOL(drm_drv_enabled);
>>>
>>> The name implies a bool return, but it's not.
>>>
>>> if (drm_drv_enabled(...)) {
>>> /* surprise, it's disabled! */
>>> }
>>>
>>
>> It used to return a bool in v2 but Thomas suggested an int instead to
>> have consistency on the errno code that was returned by the callers.
>>
>> I should probably name that function differently to avoid confusion.
>
> Yes, please.
>
drm_driver_check() maybe ?
Best regards,
--
Javier Martinez Canillas
Linux Engineering
Red Hat
On 11/5/21 11:04, Jani Nikula wrote:
> On Fri, 05 Nov 2021, Javier Martinez Canillas <[email protected]> wrote:
[snip]
>>
>> Do you envision other condition that could be added later to disable a
>> DRM driver ? Or do you think that just from a code readability point of
>> view makes worth it ?
>
> Taking a step back for perspective.
>
> I think there's broad consensus in moving the parameter to drm, naming
> the check function to drm_something_something(), and breaking the ties
> to CONFIG_VGA_CONSOLE. I appreciate the work you're doing to that
> effect.
>
Thanks, I appreciate your feedback and comments.
> I think everything beyond that is still a bit vague and/or
> contentious. So how about making the first 2-3 patches just that?
> Something we can all agree on, makes good progress, improves the kernel,
> and gives us something to build on?
>
That works for me. Thomas, do you agree with that approach ?
Best regards,
--
Javier Martinez Canillas
Linux Engineering
Red Hat
Hi
Am 05.11.21 um 13:00 schrieb Javier Martinez Canillas:
> On 11/5/21 11:04, Jani Nikula wrote:
>> On Fri, 05 Nov 2021, Javier Martinez Canillas <[email protected]> wrote:
>
> [snip]
>
>>>
>>> Do you envision other condition that could be added later to disable a
>>> DRM driver ? Or do you think that just from a code readability point of
>>> view makes worth it ?
>>
>> Taking a step back for perspective.
>>
>> I think there's broad consensus in moving the parameter to drm, naming
>> the check function to drm_something_something(), and breaking the ties
>> to CONFIG_VGA_CONSOLE. I appreciate the work you're doing to that
>> effect.
>>
>
> Thanks, I appreciate your feedback and comments.
>
>> I think everything beyond that is still a bit vague and/or
>> contentious. So how about making the first 2-3 patches just that?
>> Something we can all agree on, makes good progress, improves the kernel,
>> and gives us something to build on?
>>
>
> That works for me. Thomas, do you agree with that approach ?
Sure. I think that's more or less what I proposed in my reply to that mail.
Best regards
Thomas
>
> Best regards,
>
--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Maxfeldstr. 5, 90409 Nürnberg, Germany
(HRB 36809, AG Nürnberg)
Geschäftsführer: Ivo Totev