On Wed, Mar 24, 2021 at 11:13 AM Michel Dänzer <mic...@daenzer.net> wrote:
> On 2021-03-23 4:32 p.m., Mark Yacoub wrote: > > On Tue, Mar 23, 2021 at 11:02 AM Alex Deucher <alexdeuc...@gmail.com> > wrote: > >> > >> On Wed, Mar 10, 2021 at 11:15 AM Mark Yacoub <markyac...@chromium.org> > wrote: > >>> > >>> From: Mark Yacoub <markyac...@google.com> > >>> > >>> On initializing the framebuffer, call drm_any_plane_has_format to do a > >>> check if the modifier is supported. drm_any_plane_has_format calls > >>> dm_plane_format_mod_supported which is extended to validate that the > >>> modifier is on the list of the plane's supported modifiers. > >>> > >>> The bug was caught using igt-gpu-tools test: > kms_addfb_basic.addfb25-bad-modifier > >>> > >>> Tested on ChromeOS Zork by turning on the display, running an overlay > >>> test, and running a YT video. > >>> > >>> Cc: Alex Deucher <alexander.deuc...@amd.com> > >>> Cc: Bas Nieuwenhuizen <b...@basnieuwenhuizen.nl> > >>> Signed-off-by: default avatarMark Yacoub <markyac...@chromium.org> > >> > >> I'm not an expert with modifiers yet. Will this break chips which > >> don't currently support modifiers? > > No it shouldn't. When you don't support modifiers yet, your will > > default to Linear Modifier (DRM_FORMAT_MOD_LINEAR), > > [...] > No modifier support does not imply linear. It's generally signalled via > DRM_FORMAT_MOD_INVALID, which roughly means "tiling is determined by driver > specific mechanisms". > Doesn't quite work that way in the kernel sadly. If you don't set DRM_MODE_FB_MODIFIERS then the modifier fields have to be 0 (which happens to alias DRM_FORMAT_MOD_LINEAR and then now deprecated DRM_FORMAT_MOD_NONE). This is verified in shared drm code. (and all userspace code I've seen simply doesn't set DRM_MODE_FB_MODIFIERS if the incoming modifier is DRM_FORMAT_MOD_INVALID) > > > -- > Earthling Michel Dänzer | https://redhat.com > Libre software enthusiast | Mesa and X developer > _______________________________________________ > amd-gfx mailing list > amd-gfx@lists.freedesktop.org > https://lists.freedesktop.org/mailman/listinfo/amd-gfx >
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