If driver/HW doesn't support vblank functionality (for example UDL driver, ARCPGU driver, ...) we always have vblank->time == 0. In result we always provide zero timestamp for DRM_EVENT_FLIP_COMPLETE. This breaks userspace apps (for example weston) which relies on timestamp value.
Setup time to provide valid timestamp for DRM_EVENT_FLIP_COMPLETE event.
Cc: stable@vger.kernel.org Signed-off-by: Eugeniy Paltsev Eugeniy.Paltsev@synopsys.com --- drivers/gpu/drm/drm_vblank.c | 9 +++++++++ 1 file changed, 9 insertions(+)
diff --git a/drivers/gpu/drm/drm_vblank.c b/drivers/gpu/drm/drm_vblank.c index 28cdcf76b6f9..0d19aca48782 100644 --- a/drivers/gpu/drm/drm_vblank.c +++ b/drivers/gpu/drm/drm_vblank.c @@ -911,6 +911,15 @@ void drm_crtc_send_vblank_event(struct drm_crtc *crtc,
if (dev->num_crtcs > 0) { seq = drm_vblank_count_and_time(dev, pipe, &now); + + /* + * If driver/HW doesn't support vblank functionality we + * always have vblank->time == 0. Setup time to provide valid + * timestamp for DRM_EVENT_FLIP_COMPLETE event. + */ + if (!now && e->event.base.type == DRM_EVENT_FLIP_COMPLETE) + now = ktime_get(); + } else { seq = 0;
On Wed, Sep 26, 2018 at 05:25:35PM +0300, Eugeniy Paltsev wrote:
If those drivers don't support vblank stuff why are they calling drm_vblank_init() w/ num_crtcs > 0? If they didn't they'd take the else branch which already does what you want.
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