omap_crtc_flush() is used to wait for scheduled work to be done for the give crtc. However, it's not quite right at the moment.
omap_crtc_flush() does wait for work that is ran via vsync irq to be done. However, work is also queued to the driver's priv->wq workqueue, which is not handled by omap_crtc_flush().
Improve omap_crtc_flush() to flush the workqueue so that work there will be ran.
This fixes a race issue on module unload, where an unpin work may be on the work queue, but does not get ran before drm core starts tearing the driver down, leading to a WARN.
Signed-off-by: Tomi Valkeinen tomi.valkeinen@ti.com --- drivers/gpu/drm/omapdrm/omap_crtc.c | 31 ++++++++++++++++++++++++++----- 1 file changed, 26 insertions(+), 5 deletions(-)
diff --git a/drivers/gpu/drm/omapdrm/omap_crtc.c b/drivers/gpu/drm/omapdrm/omap_crtc.c index 3261fbf94957..506cf8bc804f 100644 --- a/drivers/gpu/drm/omapdrm/omap_crtc.c +++ b/drivers/gpu/drm/omapdrm/omap_crtc.c @@ -655,21 +655,42 @@ static void omap_crtc_post_apply(struct omap_drm_apply *apply) /* nothing needed for post-apply */ }
+static bool omap_crtc_work_pending(struct omap_crtc *omap_crtc) +{ + return !list_empty(&omap_crtc->pending_applies) || + !list_empty(&omap_crtc->queued_applies) || + omap_crtc->event || omap_crtc->old_fb; +} + +/* + * Wait for any work on the workqueue to be finished, and any work which will + * be run via vsync irq to be done. + * + * Note that work on workqueue could schedule new vsync work, and vice versa. + */ void omap_crtc_flush(struct drm_crtc *crtc) { struct omap_crtc *omap_crtc = to_omap_crtc(crtc); + struct omap_drm_private *priv = crtc->dev->dev_private; int loops = 0;
- while (!list_empty(&omap_crtc->pending_applies) || - !list_empty(&omap_crtc->queued_applies) || - omap_crtc->event || omap_crtc->old_fb) { + while (true) { + /* first flush the wq, so that any scheduled work is done */ + flush_workqueue(priv->wq); + + /* if we have nothing queued for this crtc, we're done */ + if (!omap_crtc_work_pending(omap_crtc)) + break;
if (++loops > 10) { - dev_err(crtc->dev->dev, - "omap_crtc_flush() timeout\n"); + dev_err(crtc->dev->dev, "omap_crtc_flush() timeout\n"); break; }
+ /* + * wait for a bit so that a vsync has (probably) happened, and + * that the crtc work is (probably) done. + */ schedule_timeout_uninterruptible(msecs_to_jiffies(20)); } }