[Bug 111995] New: [KBL] Black screen with I915_FORMAT_MOD_Y_TILED_CCS (Requested display configuration exceeds system DDB limitations)

[bugzilla-daemon at freedesktop.org]

https://bugs.freedesktop.org/show_bug.cgi?id=111995

            Bug ID: 111995
           Summary: [KBL] Black screen with I915_FORMAT_MOD_Y_TILED_CCS
                    (Requested display configuration exceeds system DDB
                    limitations)
           Product: DRI
           Version: unspecified
          Hardware: Other
                OS: Linux (All)
            Status: NEW
          Severity: not set
          Priority: not set
         Component: DRM/Intel
          Assignee: intel-gfx-bugs at lists.freedesktop.org
          Reporter: contact at emersion.fr
        QA Contact: intel-gfx-bugs at lists.freedesktop.org
                CC: intel-gfx-bugs at lists.freedesktop.org

This is a bug report for a KBL machine. This issue can be reproduce on both
Sway [1] and Weston. The Sway issue contains a DRM dmesg excerpt.

User-space tries to enable a pipe with a 3840x2160 XRGB8888 buffer. The buffer
is created with gbm_surface_create_with_modifiers. The primary plane supports
I915_FORMAT_MOD_Y_TILED_CCS, it seems like that's what the driver is picking.

However when scanning out the buffer, the driver bails out with "Requested
display configuration exceeds system DDB limitations". This results in a black
screen.

My main question is: both Weston and wlroots except
gbm_surface_create_with_modifiers to pick a modifier so that the buffer can be
scanned out [2]. I wouldn't expect the driver to pick a modifier that doesn't
work.

If this isn't a driver bug, should user-space force LINEAR if the atomic commit
fails? Should it prune the modifier and retry with
gbm_surface_create_with_modifiers?

[1]: https://github.com/swaywm/wlroots/issues/1852
[2]:
https://github.com/swaywm/wlroots/blob/480a31ea4e1a3aadbd053ee2a581cad5d4356876/backend/drm/renderer.c#L87

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