drm/atomic-helper: Reject legacy flips on a disabled pipe
authorDaniel Vetter <daniel.vetter@ffwll.ch>
Tue, 8 Dec 2015 08:49:20 +0000 (09:49 +0100)
committerDaniel Vetter <daniel.vetter@ffwll.ch>
Tue, 5 Jan 2016 09:07:51 +0000 (10:07 +0100)
commit4cba68507cf58db99752cf79198beb4a85a9f8ce
treece0e53f48983a7414baedc51df01a284908fe7e6
parent4cd9fa529d77dde8f760adb3d934dfac6e169b1e
drm/atomic-helper: Reject legacy flips on a disabled pipe

We want this for consistency with existing page_flip semantics.

Since this spurred quite a discussion on IRC also document why we
reject event generation when the pipe is off: It's not that it's hard
to implement, but userspace has a track recording which proves that it's
way too easy to accidentally abuse and cause havoc. We want to make
sure userspace doesn't get away with that.

v2: Somehow thought we do reject events already, but that code only
existed in my imagination ... Also suggestions from Thierry.

Cc: Daniel Stone <daniels@collabora.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Thierry Reding <thierry.reding@gmail.com>
Reviewed-by: Daniel Stone <daniels@collabora.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1449564561-3896-4-git-send-email-daniel.vetter@ffwll.ch
drivers/gpu/drm/drm_atomic.c
drivers/gpu/drm/drm_atomic_helper.c
include/drm/drm_crtc.h