On Wed, Apr 12, 2023 at 11:29:23AM -0300, Maíra Canal wrote: > Currently, drm_gem_fb_create() doesn't check if the pixel format is > supported, which can lead to the acceptance of invalid pixel formats > e.g. the acceptance of invalid modifiers. Therefore, add a check for > valid formats on drm_gem_fb_create(). > > Moreover, note that this check is only valid for atomic drivers, > because, for non-atomic drivers, checking drm_any_plane_has_format() is > not possible since the format list for the primary plane is fake, and > we'd therefor reject valid formats. > > Adding this check to drm_gem_fb_create() will guarantee that the > igt@kms_addfb_basic@addfb25-bad-modifier IGT test passes for drivers > using this callback. > > Signed-off-by: Maíra Canal <mcanal@xxxxxxxxxx> Seems sane enough, assuming all the drivers using this are happy with the baked in !modifiers -> linear assumption. That might be a good thing to highlight in the docs. Reviewed-by: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx> BTW long ago I tried to make igt check this stugg a bit more vehemently: https://patchwork.freedesktop.org/patch/239814/?series=46876&rev=1 Someone might want to pick that up again and see if it cab be makde to work with more drivers than just i915. > --- > > This patch is a recapture of a series I sent a while ago. Initially, I sent a > patch [1] similar to this one in which I introduced the format check to > drm_gem_fb_create(). > > Based on the feedback on the patch, I placed the check inside > framebuffer_check() [2] so that it wouldn't be needed to hit any driver-specific > code path when the check fails. Therefore, we could remove the check from the > specific drivers (i915, amdgpu, and vmwgfx). > > But, with some new feedback, it was shown that introducing this check inside > framebuffer_check() is problematic for the i915 driver [3]. So, I kept the check > inside the i915 driver and removed the check from amdgpu and vmwgfx [4]. But, > this yet hasn't solved the i915 problem [5]. > > As we cannot add the check inside framebuffer_check() without affecting the i915 > behavior, I propose going back to the original patch. This way we can guarantee > a more uniform behavior from the drivers that use the drm_gem_fb_create() > callback. > > [1] https://lore.kernel.org/dri-devel/20230103125322.855089-1-mcanal@xxxxxxxxxx/T/ > [2] https://lore.kernel.org/dri-devel/20230109105807.18172-1-mcanal@xxxxxxxxxx/T/ > [3] https://lore.kernel.org/dri-devel/Y8AAdW2y7zN7DCUZ@xxxxxxxxx/ > [4] https://lore.kernel.org/dri-devel/20230113112743.188486-1-mcanal@xxxxxxxxxx/T/ > [5] https://lore.kernel.org/dri-devel/Y8FXWvEhO7GCRKVJ@xxxxxxxxx/ > > Best Regards, > - Maíra Canal > > --- > Documentation/gpu/todo.rst | 7 ++----- > drivers/gpu/drm/drm_gem_framebuffer_helper.c | 9 +++++++++ > 2 files changed, 11 insertions(+), 5 deletions(-) > > diff --git a/Documentation/gpu/todo.rst b/Documentation/gpu/todo.rst > index 1f8a5ebe188e..68bdafa0284f 100644 > --- a/Documentation/gpu/todo.rst > +++ b/Documentation/gpu/todo.rst > @@ -276,11 +276,8 @@ Various hold-ups: > - Need to switch to drm_fbdev_generic_setup(), otherwise a lot of the custom fb > setup code can't be deleted. > > -- Many drivers wrap drm_gem_fb_create() only to check for valid formats. For > - atomic drivers we could check for valid formats by calling > - drm_plane_check_pixel_format() against all planes, and pass if any plane > - supports the format. For non-atomic that's not possible since like the format > - list for the primary plane is fake and we'd therefor reject valid formats. > +- Need to switch to drm_gem_fb_create(), as now drm_gem_fb_create() checks for > + valid formats for atomic drivers. > > - Many drivers subclass drm_framebuffer, we'd need a embedding compatible > version of the varios drm_gem_fb_create functions. Maybe called > diff --git a/drivers/gpu/drm/drm_gem_framebuffer_helper.c b/drivers/gpu/drm/drm_gem_framebuffer_helper.c > index e93533b86037..b8a615a138cd 100644 > --- a/drivers/gpu/drm/drm_gem_framebuffer_helper.c > +++ b/drivers/gpu/drm/drm_gem_framebuffer_helper.c > @@ -9,6 +9,7 @@ > #include <linux/module.h> > > #include <drm/drm_damage_helper.h> > +#include <drm/drm_drv.h> > #include <drm/drm_fourcc.h> > #include <drm/drm_framebuffer.h> > #include <drm/drm_gem.h> > @@ -164,6 +165,14 @@ int drm_gem_fb_init_with_funcs(struct drm_device *dev, > return -EINVAL; > } > > + if (drm_drv_uses_atomic_modeset(dev) && > + !drm_any_plane_has_format(dev, mode_cmd->pixel_format, > + mode_cmd->modifier[0])) { > + drm_dbg(dev, "Unsupported pixel format %p4cc / modifier 0x%llx\n", > + &mode_cmd->pixel_format, mode_cmd->modifier[0]); > + return -EINVAL; > + } > + > for (i = 0; i < info->num_planes; i++) { > unsigned int width = mode_cmd->width / (i ? info->hsub : 1); > unsigned int height = mode_cmd->height / (i ? info->vsub : 1); > -- > 2.39.2 -- Ville Syrjälä Intel
