[PATCH 2/6] gpu: host1x: Fix syncpoint wait return value

[Terje Bergström]

On 11.06.2013 15:09, Daniel Vetter wrote:
> Maybe it wasn't clear, but -EAGAIN does _not_ resubmit work. -EAGAIN
> is used to restart the ioctl if we had to kick a thread (to make sure
> it doesn't hold any locks), e.g. for a blocking wait on oustanding
> rendering. The codepaths taken work exactly as if the thread is
> interrupt with a signal.

You did make it clear that there's no resubmission, but other parts
confused me.

So this is used so that a legacy driver which does not do fine-grained
locking can interrupt all waits for completion for a wedged submit. This
way a driver-wide lock get unlocked, cleanup code acquires locks, does
the magic to unwedge GPU, and unlocks. Then user space can re-submit the
waits as it got -EAGAIN.

Fortunately the error code doesn't really matter as long as it's not
EAGAIN, so we can just use ETIMEDOUT as Thierry suggested in his follow-up.

Terje