[PATCH v7 02/15] gpu: host1x: Add no-recovery mode

[Dmitry Osipenko]

10.06.2021 14:04, Mikko Perttunen пишет:
> Add a new property for jobs to enable or disable recovery i.e.
> CPU increments of syncpoints to max value on job timeout. This
> allows for a more solid model for hanged jobs, where userspace
> doesn't need to guess if a syncpoint increment happened because
> the job completed, or because job timeout was triggered.

Userspace should always get proper timeout. Threshold should be wrapped
into fence. Fence's error state should be set to -ETIMEDOUT.

> On job timeout, we stop the channel, NOP all future jobs on the
> channel using the same syncpoint, mark the syncpoint as locked
> and resume the channel from the next job, if any.
> 
> The future jobs are NOPed, since because we don't do the CPU
> increments, the value of the syncpoint is no longer synchronized,
> and any waiters would become confused if a future job incremented
> the syncpoint. The syncpoint is marked locked to ensure that any
> future jobs cannot increment the syncpoint either, until the
> application has recognized the situation and reallocated the
> syncpoint.

It should be much easier to switch to DRM scheduler, removing lot's of
the old code instead of updating it with new quirks that are difficult
to follow.