The 50 ms default timeout waiting for vblanks is too small for the first vblank from the ST-Ericsson MCDE display controller over DSI. Presumably this is because the DSI display is command-mode only and the state machine will take some time setting up its state for the first display update, and we hit a timeout. 100 ms makes it pass without problems. Signed-off-by: Linus Walleij <linus.walleij@xxxxxxxxxx> --- After a quite prolonged hunting for the cause of missed vblanks in the MCDE driver I finally realized it timed out because it was simply taking some time on the first vblank. 50 ms makes sense on 60Hz monitors for sure, but an embedded DSI state machine can be slow, as it turns out. Tell me if this should be a per-driver variable and I will think of something. --- drivers/gpu/drm/drm_atomic_helper.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c index 40ac19848034..f0aa7b195d79 100644 --- a/drivers/gpu/drm/drm_atomic_helper.c +++ b/drivers/gpu/drm/drm_atomic_helper.c @@ -1424,7 +1424,7 @@ drm_atomic_helper_wait_for_vblanks(struct drm_device *dev, ret = wait_event_timeout(dev->vblank[i].queue, old_state->crtcs[i].last_vblank_count != drm_crtc_vblank_count(crtc), - msecs_to_jiffies(50)); + msecs_to_jiffies(100)); WARN(!ret, "[CRTC:%d:%s] vblank wait timed out\n", crtc->base.id, crtc->name); -- 2.20.1 _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
