On 01/05/2017 10:43 AM, Daniel Vetter wrote:
On Wed, Jan 04, 2017 at 02:00:53PM +0200, Peter Ujfalusi wrote:
Instead of scheduling the work to handle the initial delayed event, use 1s delay.
When the delayed event is handled w/o delay - in a similar matter when the poll had been initialized before drm_helper_probe_single_connector_modes() is called - it triggers a race in Optimus setups.
Fixes: 339fd36238dd ("drm: drm_probe_helper: Fix output_poll_work scheduling") Cc: stable@vger.kernel.org # v4.9 Signed-off-by: Peter Ujfalusi peter.ujfalusi@ti.com
Hi,
related bug report: https://bugs.freedesktop.org/show_bug.cgi?id=98690
Regards, Peter
drivers/gpu/drm/drm_probe_helper.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/drm_probe_helper.c b/drivers/gpu/drm/drm_probe_helper.c index 98ed110e28ed..f30c14b0a72f 100644 --- a/drivers/gpu/drm/drm_probe_helper.c +++ b/drivers/gpu/drm/drm_probe_helper.c @@ -146,8 +146,9 @@ void drm_kms_helper_poll_enable_locked(struct drm_device *dev) drm_connector_list_iter_put(&conn_iter);
if (dev->mode_config.delayed_event) {
/* Use short (1s) delay to handle the initial delayed event */
delay = 0;
delay = HZ;This smells a bit like duct-tape papering over some other race.
Yes, I agree. We could revert 339fd36238dd also to put back the duct-tape.
Lack of locking or something else. Most likely some drivers enable polling a bit too early in their load sequence.
All is pointing to Optimus. Intel and nouveau alone works, but we have failure on Optimus laptops. I have tried to narrow it down with another patch attached to the bugzilla: https://bugs.freedesktop.org/attachment.cgi?id=128742
I expected it to fix the problem. But it did not. So I'm puzzled.
And if we can't figure this out, then we need some really big FIXME: here that this papers over driver races.
Yeah, now we know that there is something wrong in some driver(s). We can hide it with delaying the poll_work. It would be great if nouveau/optimus guys would be able to take a look at this.
-Daniel
}
if (poll)
2.11.0
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