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drm: renesas: shmobile: Wait for page flip when turning CRTC off

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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.

Reviewed-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/c97d5859c43fa36043c61de28d67688ebe345092.1694767209.git.geert+renesas@glider.be
This commit is contained in:
Geert Uytterhoeven 2023-09-15 10:53:47 +02:00
parent a87e3159d4
commit b1ce7fe4c4
2 changed files with 40 additions and 0 deletions
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37
drivers/gpu/drm/renesas/shmobile/shmob_drm_crtc.c
View File

@ -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);

3
drivers/gpu/drm/renesas/shmobile/shmob_drm_crtc.h
View File

@ -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;