2018-01-22 10:35:19

by Philippe Cornu

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Subject: [PATCH] drm/stm: drv: Improve data transfers

To optimize data transfers, align pitch on 128 bytes & height
on 4 bytes. This optimization is not applicable without MMU.

Signed-off-by: Yannick Fertre <[email protected]>
Signed-off-by: Vincent Abriou <[email protected]>
Signed-off-by: Philippe Cornu <[email protected]>
---
drivers/gpu/drm/stm/drv.c | 21 +++++++++++++++++++++
1 file changed, 21 insertions(+)

diff --git a/drivers/gpu/drm/stm/drv.c b/drivers/gpu/drm/stm/drv.c
index 8fe954c27fba..c2bd9d882b93 100644
--- a/drivers/gpu/drm/stm/drv.c
+++ b/drivers/gpu/drm/stm/drv.c
@@ -31,6 +31,23 @@ static const struct drm_mode_config_funcs drv_mode_config_funcs = {
.atomic_commit = drm_atomic_helper_commit,
};

+#ifdef CONFIG_MMU
+static int stm_dumb_create(struct drm_file *file, struct drm_device *dev,
+ struct drm_mode_create_dumb *args)
+{
+ unsigned int min_pitch = DIV_ROUND_UP(args->width * args->bpp, 8);
+
+ /*
+ * in order to optimize data transfer, pitch is aligned on
+ * 128 bytes, height is aligned on 4 bytes
+ */
+ args->pitch = roundup(min_pitch, 128);
+ args->height = roundup(args->height, 4);
+
+ return drm_gem_cma_dumb_create_internal(file, dev, args);
+}
+#endif
+
DEFINE_DRM_GEM_CMA_FOPS(drv_driver_fops);

static struct drm_driver drv_driver = {
@@ -44,7 +61,11 @@ static struct drm_driver drv_driver = {
.minor = 0,
.patchlevel = 0,
.fops = &drv_driver_fops,
+#ifdef CONFIG_MMU
+ .dumb_create = stm_dumb_create,
+#else
.dumb_create = drm_gem_cma_dumb_create,
+#endif
.prime_handle_to_fd = drm_gem_prime_handle_to_fd,
.prime_fd_to_handle = drm_gem_prime_fd_to_handle,
.gem_free_object_unlocked = drm_gem_cma_free_object,
--
2.15.1



2018-01-30 08:32:57

by Benjamin Gaignard

[permalink] [raw]
Subject: Re: [PATCH] drm/stm: drv: Improve data transfers

2018-01-22 11:33 GMT+01:00 Philippe Cornu <[email protected]>:
> To optimize data transfers, align pitch on 128 bytes & height
> on 4 bytes. This optimization is not applicable without MMU.
>
> Signed-off-by: Yannick Fertre <[email protected]>
> Signed-off-by: Vincent Abriou <[email protected]>
> Signed-off-by: Philippe Cornu <[email protected]>
> ---
> drivers/gpu/drm/stm/drv.c | 21 +++++++++++++++++++++
> 1 file changed, 21 insertions(+)
>
> diff --git a/drivers/gpu/drm/stm/drv.c b/drivers/gpu/drm/stm/drv.c
> index 8fe954c27fba..c2bd9d882b93 100644
> --- a/drivers/gpu/drm/stm/drv.c
> +++ b/drivers/gpu/drm/stm/drv.c
> @@ -31,6 +31,23 @@ static const struct drm_mode_config_funcs drv_mode_config_funcs = {
> .atomic_commit = drm_atomic_helper_commit,
> };
>
> +#ifdef CONFIG_MMU
> +static int stm_dumb_create(struct drm_file *file, struct drm_device *dev,
> + struct drm_mode_create_dumb *args)
> +{
> + unsigned int min_pitch = DIV_ROUND_UP(args->width * args->bpp, 8);
> +
> + /*
> + * in order to optimize data transfer, pitch is aligned on
> + * 128 bytes, height is aligned on 4 bytes
> + */
> + args->pitch = roundup(min_pitch, 128);
> + args->height = roundup(args->height, 4);
> +
> + return drm_gem_cma_dumb_create_internal(file, dev, args);
> +}
> +#endif

I would prefer to always call stm_dumb_create (maybe renamed
stm_gem_cma_dumb_create)
and change the parameters inside if the we have MMU.

> +
> DEFINE_DRM_GEM_CMA_FOPS(drv_driver_fops);
>
> static struct drm_driver drv_driver = {
> @@ -44,7 +61,11 @@ static struct drm_driver drv_driver = {
> .minor = 0,
> .patchlevel = 0,
> .fops = &drv_driver_fops,
> +#ifdef CONFIG_MMU
> + .dumb_create = stm_dumb_create,
> +#else
> .dumb_create = drm_gem_cma_dumb_create,
> +#endif
> .prime_handle_to_fd = drm_gem_prime_handle_to_fd,
> .prime_fd_to_handle = drm_gem_prime_fd_to_handle,
> .gem_free_object_unlocked = drm_gem_cma_free_object,
> --
> 2.15.1
>