Regardless of the fence implementation, why would it be a good idea to do a full lockup recovery when some other driver isThe problem is that we need to guarantee that the lockup will be resolved eventually.
calling your wait function? That doesn't seem to be a nice thing to do, so I think a timeout is the best error you could return here,
other drivers have to deal with that anyway.
op 23-07-14 09:37, Christian KÃnig schreef:
Am 23.07.2014 09:31, schrieb Daniel Vetter:As far as I can tell it wouldn't need to be reworked for the fence implementation currently, only the moment you want to allow callers outside of radeon. :-)
On Wed, Jul 23, 2014 at 9:26 AM, Christian KÃnigWe tried this approach, but it didn't worked at all.
<deathsimple@xxxxxxxxxxx> wrote:
It's not a locking problem I'm talking about here. Radeons lockup handlingSo you don't have a timer in radeon that periodically checks whether
kicks in when anything calls into the driver from the outside, if you have a
fence wait function that's called from the outside but doesn't handle
lockups you essentially rely on somebody else calling another radeon
function for the lockup to be resolved.
progress is still being made? That's the approach we're using in i915,
together with some tricks to kick any stuck waiters so that we can
reliably step in and grab locks for the reset.
I already considered trying it again because of the upcoming fence implementation, but reconsidering that when a driver is forced to change it's handling because of the fence implementation that's just another hint that there is something wrong here.
Doing a GPU lockup recovery in the wait function would be messy even right now, you would hit a deadlock in ttm_bo_delayed_delete -> ttm_bo_cleanup_refs_and_unlock.
Regardless of the fence implementation, why would it be a good idea to do a full lockup recovery when some other driver is
calling your wait function? That doesn't seem to be a nice thing to do, so I think a timeout is the best error you could return here,
other drivers have to deal with that anyway.
~Maarten