hyperv_setup_vram tries to remove conflicting framebuffer based on
'screen_info'. As observed in past due to some bug or wrong setting
in grub, the 'screen_info' fields may not be set for Gen1, and in such
cases drm_aperture_remove_conflicting_framebuffers will not do anything
useful.
For Gen1 VMs, it should always be possible to get framebuffer
conflict removed using PCI device instead.
Fixes: a0ab5abced55 ("drm/hyperv : Removing the restruction of VRAM allocation with PCI bar size")
Signed-off-by: Saurabh Sengar <[email protected]>
---
drivers/gpu/drm/hyperv/hyperv_drm_drv.c | 24 ++++++++++++++++++++----
1 file changed, 20 insertions(+), 4 deletions(-)
diff --git a/drivers/gpu/drm/hyperv/hyperv_drm_drv.c b/drivers/gpu/drm/hyperv/hyperv_drm_drv.c
index 6d11e7938c83..b0cc974efa45 100644
--- a/drivers/gpu/drm/hyperv/hyperv_drm_drv.c
+++ b/drivers/gpu/drm/hyperv/hyperv_drm_drv.c
@@ -73,12 +73,28 @@ static int hyperv_setup_vram(struct hyperv_drm_device *hv,
struct hv_device *hdev)
{
struct drm_device *dev = &hv->dev;
+ struct pci_dev *pdev;
int ret;
- drm_aperture_remove_conflicting_framebuffers(screen_info.lfb_base,
- screen_info.lfb_size,
- false,
- &hyperv_driver);
+ if (efi_enabled(EFI_BOOT)) {
+ drm_aperture_remove_conflicting_framebuffers(screen_info.lfb_base,
+ screen_info.lfb_size,
+ false,
+ &hyperv_driver);
+ } else {
+ pdev = pci_get_device(PCI_VENDOR_ID_MICROSOFT, PCI_DEVICE_ID_HYPERV_VIDEO, NULL);
+ if (!pdev) {
+ drm_err(dev, "Unable to find PCI Hyper-V video\n");
+ return -ENODEV;
+ }
+
+ ret = drm_aperture_remove_conflicting_pci_framebuffers(pdev, &hyperv_driver);
+ pci_dev_put(pdev);
+ if (ret) {
+ drm_err(dev, "Not able to remove boot fb\n");
+ return ret;
+ }
+ }
hv->fb_size = (unsigned long)hv->mmio_megabytes * 1024 * 1024;
--
2.34.1
From: Saurabh Sengar <[email protected]> Sent: Friday, September 9, 2022 7:44 AM
>
> hyperv_setup_vram tries to remove conflicting framebuffer based on
> 'screen_info'. As observed in past due to some bug or wrong setting
> in grub, the 'screen_info' fields may not be set for Gen1, and in such
> cases drm_aperture_remove_conflicting_framebuffers will not do anything
> useful.
> For Gen1 VMs, it should always be possible to get framebuffer
> conflict removed using PCI device instead.
>
> Fixes: a0ab5abced55 ("drm/hyperv : Removing the restruction of VRAM allocation with PCI bar size")
> Signed-off-by: Saurabh Sengar <[email protected]>
> ---
> drivers/gpu/drm/hyperv/hyperv_drm_drv.c | 24 ++++++++++++++++++++----
> 1 file changed, 20 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/gpu/drm/hyperv/hyperv_drm_drv.c
> b/drivers/gpu/drm/hyperv/hyperv_drm_drv.c
> index 6d11e7938c83..b0cc974efa45 100644
> --- a/drivers/gpu/drm/hyperv/hyperv_drm_drv.c
> +++ b/drivers/gpu/drm/hyperv/hyperv_drm_drv.c
> @@ -73,12 +73,28 @@ static int hyperv_setup_vram(struct hyperv_drm_device *hv,
> struct hv_device *hdev)
> {
> struct drm_device *dev = &hv->dev;
> + struct pci_dev *pdev;
> int ret;
>
> - drm_aperture_remove_conflicting_framebuffers(screen_info.lfb_base,
> - screen_info.lfb_size,
> - false,
> - &hyperv_driver);
> + if (efi_enabled(EFI_BOOT)) {
> + drm_aperture_remove_conflicting_framebuffers(screen_info.lfb_base,
> + screen_info.lfb_size,
> + false,
> + &hyperv_driver);
> + } else {
> + pdev = pci_get_device(PCI_VENDOR_ID_MICROSOFT, PCI_DEVICE_ID_HYPERV_VIDEO, NULL);
> + if (!pdev) {
> + drm_err(dev, "Unable to find PCI Hyper-V video\n");
> + return -ENODEV;
> + }
> +
> + ret = drm_aperture_remove_conflicting_pci_framebuffers(pdev, &hyperv_driver);
> + pci_dev_put(pdev);
> + if (ret) {
> + drm_err(dev, "Not able to remove boot fb\n");
> + return ret;
> + }
> + }
>
> hv->fb_size = (unsigned long)hv->mmio_megabytes * 1024 * 1024;
>
> --
> 2.34.1
Reviewed-by: Michael Kelley <[email protected]>
Hi
Am 09.09.22 um 16:43 schrieb Saurabh Sengar:
> hyperv_setup_vram tries to remove conflicting framebuffer based on
> 'screen_info'. As observed in past due to some bug or wrong setting
> in grub, the 'screen_info' fields may not be set for Gen1, and in such
> cases drm_aperture_remove_conflicting_framebuffers will not do anything
> useful.
> For Gen1 VMs, it should always be possible to get framebuffer
> conflict removed using PCI device instead.
>
> Fixes: a0ab5abced55 ("drm/hyperv : Removing the restruction of VRAM allocation with PCI bar size")
> Signed-off-by: Saurabh Sengar <[email protected]>
> ---
> drivers/gpu/drm/hyperv/hyperv_drm_drv.c | 24 ++++++++++++++++++++----
> 1 file changed, 20 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/gpu/drm/hyperv/hyperv_drm_drv.c b/drivers/gpu/drm/hyperv/hyperv_drm_drv.c
> index 6d11e7938c83..b0cc974efa45 100644
> --- a/drivers/gpu/drm/hyperv/hyperv_drm_drv.c
> +++ b/drivers/gpu/drm/hyperv/hyperv_drm_drv.c
> @@ -73,12 +73,28 @@ static int hyperv_setup_vram(struct hyperv_drm_device *hv,
> struct hv_device *hdev)
> {
> struct drm_device *dev = &hv->dev;
> + struct pci_dev *pdev;
> int ret;
>
> - drm_aperture_remove_conflicting_framebuffers(screen_info.lfb_base,
> - screen_info.lfb_size,
> - false,
> - &hyperv_driver);
> + if (efi_enabled(EFI_BOOT)) {
> + drm_aperture_remove_conflicting_framebuffers(screen_info.lfb_base,
> + screen_info.lfb_size,
Using screen_info here seems wrong in any case. You want to remove the
framebuffer devices that conflict with your driver, which might be
unrelated to screen_info. AFAICT the correct solution would always
retrieve the PCI device for removal (i.e., always do the else branch).
Best regard
Thomas
> + false,
> + &hyperv_driver);
> + } else {
> + pdev = pci_get_device(PCI_VENDOR_ID_MICROSOFT, PCI_DEVICE_ID_HYPERV_VIDEO, NULL);
> + if (!pdev) {
> + drm_err(dev, "Unable to find PCI Hyper-V video\n");
> + return -ENODEV;
> + }
> +
> + ret = drm_aperture_remove_conflicting_pci_framebuffers(pdev, &hyperv_driver);
> + pci_dev_put(pdev);
> + if (ret) {
> + drm_err(dev, "Not able to remove boot fb\n");
> + return ret;
> + }
> + }
>
> hv->fb_size = (unsigned long)hv->mmio_megabytes * 1024 * 1024;
>
--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Maxfeldstr. 5, 90409 Nürnberg, Germany
(HRB 36809, AG Nürnberg)
Geschäftsführer: Ivo Totev
On Sat, Sep 10, 2022 at 08:11:24PM +0200, Thomas Zimmermann wrote:
> Hi
>
> Am 09.09.22 um 16:43 schrieb Saurabh Sengar:
> >hyperv_setup_vram tries to remove conflicting framebuffer based on
> >'screen_info'. As observed in past due to some bug or wrong setting
> >in grub, the 'screen_info' fields may not be set for Gen1, and in such
> >cases drm_aperture_remove_conflicting_framebuffers will not do anything
> >useful.
> >For Gen1 VMs, it should always be possible to get framebuffer
> >conflict removed using PCI device instead.
> >
> >Fixes: a0ab5abced55 ("drm/hyperv : Removing the restruction of VRAM allocation with PCI bar size")
> >Signed-off-by: Saurabh Sengar <[email protected]>
> >---
> > drivers/gpu/drm/hyperv/hyperv_drm_drv.c | 24 ++++++++++++++++++++----
> > 1 file changed, 20 insertions(+), 4 deletions(-)
> >
> >diff --git a/drivers/gpu/drm/hyperv/hyperv_drm_drv.c b/drivers/gpu/drm/hyperv/hyperv_drm_drv.c
> >index 6d11e7938c83..b0cc974efa45 100644
> >--- a/drivers/gpu/drm/hyperv/hyperv_drm_drv.c
> >+++ b/drivers/gpu/drm/hyperv/hyperv_drm_drv.c
> >@@ -73,12 +73,28 @@ static int hyperv_setup_vram(struct hyperv_drm_device *hv,
> > struct hv_device *hdev)
> > {
> > struct drm_device *dev = &hv->dev;
> >+ struct pci_dev *pdev;
> > int ret;
> >- drm_aperture_remove_conflicting_framebuffers(screen_info.lfb_base,
> >- screen_info.lfb_size,
> >- false,
> >- &hyperv_driver);
> >+ if (efi_enabled(EFI_BOOT)) {
> >+ drm_aperture_remove_conflicting_framebuffers(screen_info.lfb_base,
> >+ screen_info.lfb_size,
>
> Using screen_info here seems wrong in any case. You want to remove
> the framebuffer devices that conflict with your driver, which might
> be unrelated to screen_info. AFAICT the correct solution would
> always retrieve the PCI device for removal (i.e., always do the else
> branch).
In a Gen2 VM, the Hyper-V frame buffer device is presented only as a VMbus device.
It's not presented as a PCI device like it is in a Gen1 VM. This would have worked
if we had the frame buffer device available as PCI device in Gen2 but unfortunately
thats not the case here.
Regards,
Saurabh
>
> Best regard
> Thomas
>
> >+ false,
> >+ &hyperv_driver);
> >+ } else {
> >+ pdev = pci_get_device(PCI_VENDOR_ID_MICROSOFT, PCI_DEVICE_ID_HYPERV_VIDEO, NULL);
> >+ if (!pdev) {
> >+ drm_err(dev, "Unable to find PCI Hyper-V video\n");
> >+ return -ENODEV;
> >+ }
> >+
> >+ ret = drm_aperture_remove_conflicting_pci_framebuffers(pdev, &hyperv_driver);
> >+ pci_dev_put(pdev);
> >+ if (ret) {
> >+ drm_err(dev, "Not able to remove boot fb\n");
> >+ return ret;
> >+ }
> >+ }
> > hv->fb_size = (unsigned long)hv->mmio_megabytes * 1024 * 1024;
>
> --
> Thomas Zimmermann
> Graphics Driver Developer
> SUSE Software Solutions Germany GmbH
> Maxfeldstr. 5, 90409 N?rnberg, Germany
> (HRB 36809, AG N?rnberg)
> Gesch?ftsf?hrer: Ivo Totev
Hi
Am 11.09.22 um 18:21 schrieb Saurabh Singh Sengar:
> On Sat, Sep 10, 2022 at 08:11:24PM +0200, Thomas Zimmermann wrote:
>> Hi
>>
>> Am 09.09.22 um 16:43 schrieb Saurabh Sengar:
>>> hyperv_setup_vram tries to remove conflicting framebuffer based on
>>> 'screen_info'. As observed in past due to some bug or wrong setting
>>> in grub, the 'screen_info' fields may not be set for Gen1, and in such
>>> cases drm_aperture_remove_conflicting_framebuffers will not do anything
>>> useful.
>>> For Gen1 VMs, it should always be possible to get framebuffer
>>> conflict removed using PCI device instead.
>>>
>>> Fixes: a0ab5abced55 ("drm/hyperv : Removing the restruction of VRAM allocation with PCI bar size")
>>> Signed-off-by: Saurabh Sengar <[email protected]>
>>> ---
>>> drivers/gpu/drm/hyperv/hyperv_drm_drv.c | 24 ++++++++++++++++++++----
>>> 1 file changed, 20 insertions(+), 4 deletions(-)
>>>
>>> diff --git a/drivers/gpu/drm/hyperv/hyperv_drm_drv.c b/drivers/gpu/drm/hyperv/hyperv_drm_drv.c
>>> index 6d11e7938c83..b0cc974efa45 100644
>>> --- a/drivers/gpu/drm/hyperv/hyperv_drm_drv.c
>>> +++ b/drivers/gpu/drm/hyperv/hyperv_drm_drv.c
>>> @@ -73,12 +73,28 @@ static int hyperv_setup_vram(struct hyperv_drm_device *hv,
>>> struct hv_device *hdev)
>>> {
>>> struct drm_device *dev = &hv->dev;
>>> + struct pci_dev *pdev;
>>> int ret;
>>> - drm_aperture_remove_conflicting_framebuffers(screen_info.lfb_base,
>>> - screen_info.lfb_size,
>>> - false,
>>> - &hyperv_driver);
>>> + if (efi_enabled(EFI_BOOT)) {
>>> + drm_aperture_remove_conflicting_framebuffers(screen_info.lfb_base,
>>> + screen_info.lfb_size,
>>
>> Using screen_info here seems wrong in any case. You want to remove
>> the framebuffer devices that conflict with your driver, which might
>> be unrelated to screen_info. AFAICT the correct solution would
>> always retrieve the PCI device for removal (i.e., always do the else
>> branch).
>
> In a Gen2 VM, the Hyper-V frame buffer device is presented only as a VMbus device.
> It's not presented as a PCI device like it is in a Gen1 VM. This would have worked
> if we had the frame buffer device available as PCI device in Gen2 but unfortunately
> thats not the case here.
Thanks for explaining. There is an instance of struct hv_device passed
to the probe function. I suspect you cannot get the framebuffer range
from this instance (e.g., via the device's platform_data)?
If you absolutely can't get the actual memory region from the device,
it's better to remove all framebuffers via
drm_aperture_remove_framebuffers() than to use screen_info.
Best regards
Thomas
>
> Regards,
> Saurabh
>
>>
>> Best regard
>> Thomas
>>
>>> + false,
>>> + &hyperv_driver);
>>> + } else {
>>> + pdev = pci_get_device(PCI_VENDOR_ID_MICROSOFT, PCI_DEVICE_ID_HYPERV_VIDEO, NULL);
>>> + if (!pdev) {
>>> + drm_err(dev, "Unable to find PCI Hyper-V video\n");
>>> + return -ENODEV;
>>> + }
>>> +
>>> + ret = drm_aperture_remove_conflicting_pci_framebuffers(pdev, &hyperv_driver);
>>> + pci_dev_put(pdev);
>>> + if (ret) {
>>> + drm_err(dev, "Not able to remove boot fb\n");
>>> + return ret;
>>> + }
>>> + }
>>> hv->fb_size = (unsigned long)hv->mmio_megabytes * 1024 * 1024;
>>
>> --
>> Thomas Zimmermann
>> Graphics Driver Developer
>> SUSE Software Solutions Germany GmbH
>> Maxfeldstr. 5, 90409 Nürnberg, Germany
>> (HRB 36809, AG Nürnberg)
>> Geschäftsführer: Ivo Totev
>
>
>
--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Maxfeldstr. 5, 90409 Nürnberg, Germany
(HRB 36809, AG Nürnberg)
Geschäftsführer: Ivo Totev
Hi
Am 13.09.22 um 17:15 schrieb Saurabh Singh Sengar:
> On Mon, Sep 12, 2022 at 09:03:53AM +0200, Thomas Zimmermann wrote:
>> Hi
>>
>> Am 11.09.22 um 18:21 schrieb Saurabh Singh Sengar:
>>> On Sat, Sep 10, 2022 at 08:11:24PM +0200, Thomas Zimmermann wrote:
>>>> Hi
>>>>
>>>> Am 09.09.22 um 16:43 schrieb Saurabh Sengar:
>>>>> hyperv_setup_vram tries to remove conflicting framebuffer based on
>>>>> 'screen_info'. As observed in past due to some bug or wrong setting
>>>>> in grub, the 'screen_info' fields may not be set for Gen1, and in such
>>>>> cases drm_aperture_remove_conflicting_framebuffers will not do anything
>>>>> useful.
>>>>> For Gen1 VMs, it should always be possible to get framebuffer
>>>>> conflict removed using PCI device instead.
>>>>>
>>>>> Fixes: a0ab5abced55 ("drm/hyperv : Removing the restruction of VRAM allocation with PCI bar size")
>>>>> Signed-off-by: Saurabh Sengar <[email protected]>
>>>>> ---
>>>>> drivers/gpu/drm/hyperv/hyperv_drm_drv.c | 24 ++++++++++++++++++++----
>>>>> 1 file changed, 20 insertions(+), 4 deletions(-)
>>>>>
>>>>> diff --git a/drivers/gpu/drm/hyperv/hyperv_drm_drv.c b/drivers/gpu/drm/hyperv/hyperv_drm_drv.c
>>>>> index 6d11e7938c83..b0cc974efa45 100644
>>>>> --- a/drivers/gpu/drm/hyperv/hyperv_drm_drv.c
>>>>> +++ b/drivers/gpu/drm/hyperv/hyperv_drm_drv.c
>>>>> @@ -73,12 +73,28 @@ static int hyperv_setup_vram(struct hyperv_drm_device *hv,
>>>>> struct hv_device *hdev)
>>>>> {
>>>>> struct drm_device *dev = &hv->dev;
>>>>> + struct pci_dev *pdev;
>>>>> int ret;
>>>>> - drm_aperture_remove_conflicting_framebuffers(screen_info.lfb_base,
>>>>> - screen_info.lfb_size,
>>>>> - false,
>>>>> - &hyperv_driver);
>>>>> + if (efi_enabled(EFI_BOOT)) {
>>>>> + drm_aperture_remove_conflicting_framebuffers(screen_info.lfb_base,
>>>>> + screen_info.lfb_size,
>>>>
>>>> Using screen_info here seems wrong in any case. You want to remove
>>>> the framebuffer devices that conflict with your driver, which might
>>>> be unrelated to screen_info. AFAICT the correct solution would
>>>> always retrieve the PCI device for removal (i.e., always do the else
>>>> branch).
>>>
>>> In a Gen2 VM, the Hyper-V frame buffer device is presented only as a VMbus device.
>>> It's not presented as a PCI device like it is in a Gen1 VM. This would have worked
>>> if we had the frame buffer device available as PCI device in Gen2 but unfortunately
>>> thats not the case here.
>>
>> Thanks for explaining. There is an instance of struct hv_device
>> passed to the probe function. I suspect you cannot get the
>> framebuffer range from this instance (e.g., via the device's
>> platform_data)?
>>
>> If you absolutely can't get the actual memory region from the
>> device, it's better to remove all framebuffers via
>> drm_aperture_remove_framebuffers() than to use screen_info.
>>
>> Best regards
>> Thomas
>
> Thanks for your suggestion, and I thought of using drm_aperture_remove_framebuffers
> here, but this driver will be used in many different systems with many other graphics
> devices (GPU etc). Removing all the framebuffer is a bit blunt approach which may disturb
> the devices we are not intended to and which are even outside of the HyperV MMIO region.
> I feel this API use will be risky, and I would like to stick to the earlier method which
> is proven to be working for many years and we are sure it won't disturb anyone outside
> MMIO region.
But the problem with the current code is that you also remove the driver
that covers the boot-up graphics, even if it's not even a hyperv device.
That's why I said that you should try to detect if the hyperv device
you're creating actually uses the screen_info when you create the device.
Set that information as device data and look it up in the hyperv-drm
driver. If no such screen_info data is attached to the device, you don't
have to remove conflicting framebuffers at all.
Best regards
Thomas
>
> Regards,
> Saurabh
>>
>>>
>>> Regards,
>>> Saurabh
>>>
>>>>
>>>> Best regard
>>>> Thomas
>>>>
>>>>> + false,
>>>>> + &hyperv_driver);
>>>>> + } else {
>>>>> + pdev = pci_get_device(PCI_VENDOR_ID_MICROSOFT, PCI_DEVICE_ID_HYPERV_VIDEO, NULL);
>>>>> + if (!pdev) {
>>>>> + drm_err(dev, "Unable to find PCI Hyper-V video\n");
>>>>> + return -ENODEV;
>>>>> + }
>>>>> +
>>>>> + ret = drm_aperture_remove_conflicting_pci_framebuffers(pdev, &hyperv_driver);
>>>>> + pci_dev_put(pdev);
>>>>> + if (ret) {
>>>>> + drm_err(dev, "Not able to remove boot fb\n");
>>>>> + return ret;
>>>>> + }
>>>>> + }
>>>>> hv->fb_size = (unsigned long)hv->mmio_megabytes * 1024 * 1024;
>>>>
>>>> --
>>>> Thomas Zimmermann
>>>> Graphics Driver Developer
>>>> SUSE Software Solutions Germany GmbH
>>>> Maxfeldstr. 5, 90409 Nürnberg, Germany
>>>> (HRB 36809, AG Nürnberg)
>>>> Geschäftsführer: Ivo Totev
>>>
>>>
>>>
>>
>> --
>> Thomas Zimmermann
>> Graphics Driver Developer
>> SUSE Software Solutions Germany GmbH
>> Maxfeldstr. 5, 90409 Nürnberg, Germany
>> (HRB 36809, AG Nürnberg)
>> Geschäftsführer: Ivo Totev
>
>
>
--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Maxfeldstr. 5, 90409 Nürnberg, Germany
(HRB 36809, AG Nürnberg)
Geschäftsführer: Ivo Totev
On Mon, Sep 12, 2022 at 09:03:53AM +0200, Thomas Zimmermann wrote:
> Hi
>
> Am 11.09.22 um 18:21 schrieb Saurabh Singh Sengar:
> >On Sat, Sep 10, 2022 at 08:11:24PM +0200, Thomas Zimmermann wrote:
> >>Hi
> >>
> >>Am 09.09.22 um 16:43 schrieb Saurabh Sengar:
> >>>hyperv_setup_vram tries to remove conflicting framebuffer based on
> >>>'screen_info'. As observed in past due to some bug or wrong setting
> >>>in grub, the 'screen_info' fields may not be set for Gen1, and in such
> >>>cases drm_aperture_remove_conflicting_framebuffers will not do anything
> >>>useful.
> >>>For Gen1 VMs, it should always be possible to get framebuffer
> >>>conflict removed using PCI device instead.
> >>>
> >>>Fixes: a0ab5abced55 ("drm/hyperv : Removing the restruction of VRAM allocation with PCI bar size")
> >>>Signed-off-by: Saurabh Sengar <[email protected]>
> >>>---
> >>> drivers/gpu/drm/hyperv/hyperv_drm_drv.c | 24 ++++++++++++++++++++----
> >>> 1 file changed, 20 insertions(+), 4 deletions(-)
> >>>
> >>>diff --git a/drivers/gpu/drm/hyperv/hyperv_drm_drv.c b/drivers/gpu/drm/hyperv/hyperv_drm_drv.c
> >>>index 6d11e7938c83..b0cc974efa45 100644
> >>>--- a/drivers/gpu/drm/hyperv/hyperv_drm_drv.c
> >>>+++ b/drivers/gpu/drm/hyperv/hyperv_drm_drv.c
> >>>@@ -73,12 +73,28 @@ static int hyperv_setup_vram(struct hyperv_drm_device *hv,
> >>> struct hv_device *hdev)
> >>> {
> >>> struct drm_device *dev = &hv->dev;
> >>>+ struct pci_dev *pdev;
> >>> int ret;
> >>>- drm_aperture_remove_conflicting_framebuffers(screen_info.lfb_base,
> >>>- screen_info.lfb_size,
> >>>- false,
> >>>- &hyperv_driver);
> >>>+ if (efi_enabled(EFI_BOOT)) {
> >>>+ drm_aperture_remove_conflicting_framebuffers(screen_info.lfb_base,
> >>>+ screen_info.lfb_size,
> >>
> >>Using screen_info here seems wrong in any case. You want to remove
> >>the framebuffer devices that conflict with your driver, which might
> >>be unrelated to screen_info. AFAICT the correct solution would
> >>always retrieve the PCI device for removal (i.e., always do the else
> >>branch).
> >
> >In a Gen2 VM, the Hyper-V frame buffer device is presented only as a VMbus device.
> >It's not presented as a PCI device like it is in a Gen1 VM. This would have worked
> >if we had the frame buffer device available as PCI device in Gen2 but unfortunately
> >thats not the case here.
>
> Thanks for explaining. There is an instance of struct hv_device
> passed to the probe function. I suspect you cannot get the
> framebuffer range from this instance (e.g., via the device's
> platform_data)?
>
> If you absolutely can't get the actual memory region from the
> device, it's better to remove all framebuffers via
> drm_aperture_remove_framebuffers() than to use screen_info.
>
> Best regards
> Thomas
Thanks for your suggestion, and I thought of using drm_aperture_remove_framebuffers
here, but this driver will be used in many different systems with many other graphics
devices (GPU etc). Removing all the framebuffer is a bit blunt approach which may disturb
the devices we are not intended to and which are even outside of the HyperV MMIO region.
I feel this API use will be risky, and I would like to stick to the earlier method which
is proven to be working for many years and we are sure it won't disturb anyone outside
MMIO region.
Regards,
Saurabh
>
> >
> >Regards,
> >Saurabh
> >
> >>
> >>Best regard
> >>Thomas
> >>
> >>>+ false,
> >>>+ &hyperv_driver);
> >>>+ } else {
> >>>+ pdev = pci_get_device(PCI_VENDOR_ID_MICROSOFT, PCI_DEVICE_ID_HYPERV_VIDEO, NULL);
> >>>+ if (!pdev) {
> >>>+ drm_err(dev, "Unable to find PCI Hyper-V video\n");
> >>>+ return -ENODEV;
> >>>+ }
> >>>+
> >>>+ ret = drm_aperture_remove_conflicting_pci_framebuffers(pdev, &hyperv_driver);
> >>>+ pci_dev_put(pdev);
> >>>+ if (ret) {
> >>>+ drm_err(dev, "Not able to remove boot fb\n");
> >>>+ return ret;
> >>>+ }
> >>>+ }
> >>> hv->fb_size = (unsigned long)hv->mmio_megabytes * 1024 * 1024;
> >>
> >>--
> >>Thomas Zimmermann
> >>Graphics Driver Developer
> >>SUSE Software Solutions Germany GmbH
> >>Maxfeldstr. 5, 90409 N?rnberg, Germany
> >>(HRB 36809, AG N?rnberg)
> >>Gesch?ftsf?hrer: Ivo Totev
> >
> >
> >
>
> --
> Thomas Zimmermann
> Graphics Driver Developer
> SUSE Software Solutions Germany GmbH
> Maxfeldstr. 5, 90409 N?rnberg, Germany
> (HRB 36809, AG N?rnberg)
> Gesch?ftsf?hrer: Ivo Totev