drm/fb-helper: Blacklist writeback when adding connectors to fbdev
Writeback connectors do not produce any on-screen output and require special care for use. Such connectors are hidden from enumeration in DRM resources by default, but they are still picked-up by fbdev. This makes rather little sense since fbdev is not really adapted for dealing with writeback. Moreover, this is also a source of issues when userspace disables the CRTC (and associated plane) without detaching the CRTC from the connector (which is hidden by default). In this case, the connector is still using the CRTC, leading to am "enabled/connectors mismatch" and eventually the failure of the associated atomic commit. This situation happens with VC4 testing under IGT GPU Tools. Filter out writeback connectors in the fbdev helper to solve this. Signed-off-by: Paul Kocialkowski <paul.kocialkowski@bootlin.com> Reviewed-by: Boris Brezillon <boris.brezillon@bootlin.com> Reviewed-by: Maxime Ripard <maxime.ripard@bootlin.com> Tested-by: Maxime Ripard <maxime.ripard@bootlin.com> Fixes: 935774cd ("drm: Add writeback connector type") Cc: <stable@vger.kernel.org> # v4.19+ Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch> Link: https://patchwork.freedesktop.org/patch/msgid/20181115163248.21168-1-paul.kocialkowski@bootlin.com
Showing
Please register or sign in to comment