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

["Ville Syrjälä" <ville.syrjala@linux.intel.com>]

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@linux.intel.com> wrote:
> >> On Mon, Mar 05, 2018 at 12:59:00PM -0800, Eric Anholt wrote:
> >>> Ville Syrjala <ville.syrjala@linux.intel.com> writes:
> >>>
> >>>> From: Ville Syrjälä <ville.syrjala@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@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?

In amdgpu_dm_plane_init().

drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c-      switch (aplane->base.type) {
drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c-      case DRM_PLANE_TYPE_PRIMARY:
drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c:              aplane->base.format_default = true;
                                                                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c-
drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c-              res = drm_universal_plane_init(

> 
> 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.
> 
> 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
> >> _______________________________________________
> >> dri-devel mailing list
> >> dri-devel@lists.freedesktop.org
> >> https://lists.freedesktop.org/mailman/listinfo/dri-devel

-- 
Ville Syrjälä
Intel OTC
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