Turning a CRTC off will prevent a queued page flip from ever completing, potentially confusing userspace. Wait for queued page flips to complete before turning the CRTC off to avoid this. Signed-off-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx> Reviewed-by: Laurent Pinchart <laurent.pinchart+renesas@xxxxxxxxxxxxxxxx> --- v2: - Add Reviewed-by. --- .../gpu/drm/renesas/shmobile/shmob_drm_crtc.c | 37 +++++++++++++++++++ .../gpu/drm/renesas/shmobile/shmob_drm_crtc.h | 3 ++ 2 files changed, 40 insertions(+) diff --git a/drivers/gpu/drm/renesas/shmobile/shmob_drm_crtc.c b/drivers/gpu/drm/renesas/shmobile/shmob_drm_crtc.c index 0adf5d33ba31695e..20adb9d2fa178250 100644 --- a/drivers/gpu/drm/renesas/shmobile/shmob_drm_crtc.c +++ b/drivers/gpu/drm/renesas/shmobile/shmob_drm_crtc.c @@ -50,11 +50,40 @@ void shmob_drm_crtc_finish_page_flip(struct shmob_drm_crtc *scrtc) scrtc->event = NULL; if (event) { drm_crtc_send_vblank_event(&scrtc->base, event); + wake_up(&scrtc->flip_wait); drm_crtc_vblank_put(&scrtc->base); } spin_unlock_irqrestore(&dev->event_lock, flags); } +static bool shmob_drm_crtc_page_flip_pending(struct shmob_drm_crtc *scrtc) +{ + struct drm_device *dev = scrtc->base.dev; + unsigned long flags; + bool pending; + + spin_lock_irqsave(&dev->event_lock, flags); + pending = scrtc->event != NULL; + spin_unlock_irqrestore(&dev->event_lock, flags); + + return pending; +} + +static void shmob_drm_crtc_wait_page_flip(struct shmob_drm_crtc *scrtc) +{ + struct drm_crtc *crtc = &scrtc->base; + struct shmob_drm_device *sdev = to_shmob_device(crtc->dev); + + if (wait_event_timeout(scrtc->flip_wait, + !shmob_drm_crtc_page_flip_pending(scrtc), + msecs_to_jiffies(50))) + return; + + dev_warn(sdev->dev, "page flip timeout\n"); + + shmob_drm_crtc_finish_page_flip(scrtc); +} + /* ----------------------------------------------------------------------------- * CRTC */ @@ -253,6 +282,12 @@ static void shmob_drm_crtc_stop(struct shmob_drm_crtc *scrtc) if (!scrtc->started) return; + /* + * Wait for page flip completion before stopping the CRTC as userspace + * expects page flips to eventually complete. + */ + shmob_drm_crtc_wait_page_flip(scrtc); + /* Stop the LCDC. */ shmob_drm_crtc_start_stop(scrtc, false); @@ -463,6 +498,8 @@ int shmob_drm_crtc_create(struct shmob_drm_device *sdev) unsigned int i; int ret; + init_waitqueue_head(&sdev->crtc.flip_wait); + sdev->crtc.dpms = DRM_MODE_DPMS_OFF; primary = shmob_drm_plane_create(sdev, DRM_PLANE_TYPE_PRIMARY, 0); diff --git a/drivers/gpu/drm/renesas/shmobile/shmob_drm_crtc.h b/drivers/gpu/drm/renesas/shmobile/shmob_drm_crtc.h index 2c6d7541427581a6..b9863e026e8a9b83 100644 --- a/drivers/gpu/drm/renesas/shmobile/shmob_drm_crtc.h +++ b/drivers/gpu/drm/renesas/shmobile/shmob_drm_crtc.h @@ -14,6 +14,8 @@ #include <drm/drm_connector.h> #include <drm/drm_encoder.h> +#include <linux/wait.h> + #include <video/videomode.h> struct drm_pending_vblank_event; @@ -24,6 +26,7 @@ struct shmob_drm_crtc { struct drm_crtc base; struct drm_pending_vblank_event *event; + wait_queue_head_t flip_wait; int dpms; const struct shmob_drm_format_info *format; -- 2.34.1