This patchset fixes a few issues with use of wait for vblank in exynos drm.
Please apply these three patches without "drm/exynos: release fb pended by page flip" patch.
Patch 1: modify wait for vsync functions to use wait queues This modifies the wait_for_vblank functions to use wait queues thus ensuring that the current task goes to sleep without taking up CPU while waiting.
Patch 2: move wait_for_vblank to manager_ops Currently, we do not call wait for vblank if encoder is in DPMS_OFF state inside exynos_drm_encoder_complete_scanout function. This is because wait for vblank is treated as an overlay op. This can be modified to a manager_op thus removing the above check for DPMS_OFF. This fixes a crash while removing a fb. While removing the current fb (crtc->fb == fb) the encoder dpms off is called and then the framebuffer is removed. So in this case, the wait for vblank is not called thus leading to a crash (since fb might get removed before dma is finished)
Patch 3: do not disable crtc if already off We should not disable the overlay if the crtc is in DPMS_OFF state. Also, the disable function should not call DPMS_OFF of the crtc. This is required to ensure we are able to wait for vblank before freeing any framebuffers after disabling the crtc.
With these three patches and without "drm/exynos: release fb pended by page flip" I could not find any crash/page_fault in drm with fimd/hdmi during hotplug and page flips.
Prathyush K (3): drm/exynos: modify wait for vsync functions to use wait queues drm/exynos: move wait_for_vblank to manager_ops drm/exynos: do not disable crtc if already off
drivers/gpu/drm/exynos/exynos_drm_crtc.c | 6 +++- drivers/gpu/drm/exynos/exynos_drm_drv.h | 20 ++------------ drivers/gpu/drm/exynos/exynos_drm_encoder.c | 15 +++-------- drivers/gpu/drm/exynos/exynos_drm_fimd.c | 37 ++++++++++++++++++-------- drivers/gpu/drm/exynos/exynos_drm_hdmi.c | 22 ++++++++-------- drivers/gpu/drm/exynos/exynos_drm_hdmi.h | 2 +- drivers/gpu/drm/exynos/exynos_mixer.c | 37 +++++++++++++++++--------- 7 files changed, 73 insertions(+), 66 deletions(-)