On Wed, Jul 23, 2014 at 10:46 AM, Christian KÃnig
<deathsimple@xxxxxxxxxxx> wrote:
Am 23.07.2014 10:42, schrieb Daniel Vetter:I disagree - the entire point of fences is that we can do multi-gpu
On Wed, Jul 23, 2014 at 10:25 AM, Maarten Lankhorst
<maarten.lankhorst@xxxxxxxxxxxxx> wrote:
In this case if the sync was to i915 the i915 lockup procedure would takeActually the i915 reset stuff relies crucially on being able to kick
care of itself. It wouldn't fix radeon, but it would at least unblock your
intel card again. I haven't specifically added a special case to attempt to
unblock external fences, but I've considered it. :-)
all waiters holding driver locks. Since the current fence code only
exposes an opaque wait function without exposing the underlying wait
queue we won't be able to sleep on both the fence queue and the reset
queue. So would pose a problem if we add fence_wait calls to our
driver.
And apart from that I really think that I misunderstood Maarten. But his
explanation sounds like i915 would do a reset because Radeon is locked up,
right?
Well if that's really the case then I would question the interface even
more, cause that is really nonsense.
work asynchronously. So by the time we'll notice that radeon's dead we
have accepted the batch from userspace already. The only way to get
rid of it again is through our reset machinery, which also tells
userspace that we couldn't execute the batch. Whether we actually need
to do a hw reset depends upon whether we've committed the batch to the
hw already. Atm that's always the case, but the scheduler will change
that. So I have no issues with intel doing a reset when other drivers
don't signal fences.
Also this isn't a problem with the interface really, but with the
current implementation for radeon. And getting cross-driver reset
notifications right will require more work either way.
-Daniel