[Intel-gfx] [PATCH 1/3] drm: Make sure at least one plane supports the fb format

[Harry Wentland]

On 2018-03-06 05:35 AM, Daniel Vetter wrote:
> On Mon, Mar 05, 2018 at 05:44:16PM -0500, Harry Wentland wrote:
>> On 2018-03-05 04:33 PM, Alex Deucher wrote:
>>> On Mon, Mar 5, 2018 at 4:15 PM, Ville Syrjälä
>>> <ville.syrjala at linux.intel.com> wrote:
>>>> On Mon, Mar 05, 2018 at 12:59:00PM -0800, Eric Anholt wrote:
>>>>> Ville Syrjala <ville.syrjala at linux.intel.com> writes:
>>>>>
>>>>>> From: Ville Syrjälä <ville.syrjala at linux.intel.com>
>>>>>>
>>>>>> To make life easier for drivers, let's have the core check that the
>>>>>> requested pixel format is supported by at least one plane when creating
>>>>>> a new framebuffer.
>>>>>>
>>>>>> Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
>>>>>> ---
>>>>>>  drivers/gpu/drm/drm_framebuffer.c | 26 ++++++++++++++++++++++++++
>>>>>>  1 file changed, 26 insertions(+)
>>>>>>
>>>>>> diff --git a/drivers/gpu/drm/drm_framebuffer.c b/drivers/gpu/drm/drm_framebuffer.c
>>>>>> index c0530a1af5e3..155b21e579c4 100644
>>>>>> --- a/drivers/gpu/drm/drm_framebuffer.c
>>>>>> +++ b/drivers/gpu/drm/drm_framebuffer.c
>>>>>> @@ -152,6 +152,23 @@ static int fb_plane_height(int height,
>>>>>>     return DIV_ROUND_UP(height, format->vsub);
>>>>>>  }
>>>>>>
>>>>>> +static bool planes_have_format(struct drm_device *dev, u32 format)
>>>>>> +{
>>>>>> +   struct drm_plane *plane;
>>>>>> +
>>>>>> +   /* TODO: maybe maintain a device level format list? */
>>>>>> +   drm_for_each_plane(plane, dev) {
>>>>>> +           int i;
>>>>>> +
>>>>>> +           for (i = 0; i < plane->format_count; i++) {
>>>>>> +                   if (plane->format_types[i] == format)
>>>>>> +                           return true;
>>>>>> +           }
>>>>>> +   }
>>>>>> +
>>>>>> +   return false;
>>>>>> +}
>>>>>> +
>>>>>>  static int framebuffer_check(struct drm_device *dev,
>>>>>>                          const struct drm_mode_fb_cmd2 *r)
>>>>>>  {
>>>>>> @@ -168,6 +185,15 @@ static int framebuffer_check(struct drm_device *dev,
>>>>>>             return -EINVAL;
>>>>>>     }
>>>>>>
>>>>>> +   if (!planes_have_format(dev, r->pixel_format)) {
>>>>>> +           struct drm_format_name_buf format_name;
>>>>>> +
>>>>>> +           DRM_DEBUG_KMS("unsupported framebuffer format %s\n",
>>>>>> +                         drm_get_format_name(r->pixel_format,
>>>>>> +                                             &format_name));
>>>>>> +           return -EINVAL;
>>>>>> +   }
>>>>>> +
>>>>>
>>>>> Won't this break KMS on things like the radeon driver, which doesn't do
>>>>> planes?  Maybe check if any universal planes have been registered and
>>>>> only do the check in that case?
>>>>
>>>> Hmm. I thought we add the implicit planes always. Apparently
>>>> drm_crtc_init() adds a primary with X/ARGB8888, but no more. So
>>>> this would break all other formats, which is probably a bit too
>>>> aggressive.
>>>>
>>>> I guess I could just skip the check in case any plane has
>>>> plane->format_default set. That should be indicating that the driver
>>>> doesn't do planes fully. Oh, why exactly is amggpu setting that flag?
>>>> Harry?
>>>
>>> Probably leftover from DC bringup?
>>
>> I'm not sure if I'm following. Which flag are we talking about?
>>
>> Is the concern the DC driver or amdgpu with DC (or radeon)?
>>
>> DC does not call drm_crtc_init(). It initializes universal planes in amdgpu_dm_initialize_drm_device() -> amdgpu_dm_plane_init().
>>
>> From a quick glance this patch looks fine by me.
> 
> From amdgpu_dm_plane_init:
> 
> 		aplane->base.format_default = true;
> ^^ this is entirely bogus, pls remove.
> 

Makes sense. At one point we had a comment "for legacy code only" but that got lost. I'll clean it up.

Harry

> 		res = drm_universal_plane_init(
> 				dm->adev->ddev,
> 				&aplane->base,
> 				possible_crtcs,
> 				&dm_plane_funcs,
> 				rgb_formats,
> 				ARRAY_SIZE(rgb_formats),
> 				NULL, aplane->base.type, NULL);
> 
> 
> Wrt discussions: Also checking whether any plane has set
> plane->format_default and aborting the check should keep old kms drivers
> working I hope.
> 
> Cheers, Daniel
> 
>>
>> Harry
>>
>>>
>>> Alex
>>>
>>>>
>>>>>
>>>>> Also, "any_planes_have_format()" might be slightly more descriptive.
>>>>
>>>> Or any_plane_has_format()? Is that more englishy? :)
>>>>
>>>> --
>>>> Ville Syrjälä
>>>> Intel OTC
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