On 09.01.2025 17:58, Danilo Krummrich wrote: > On Thu, Jan 09, 2025 at 10:55:53AM +1000, Dave Airlie wrote: >> From: Dave Airlie <airlied@xxxxxxxxxx> >> >> This is the 3rd iteration of this after talking to Ben and >> Danilo, I think this makes sense now. >> >> The fence sync logic doesn't handle a fence sync across devices >> as it tries to write to a channel offset from one device into >> the fence bo from a different device, which won't work so well. >> >> This patch fixes that to avoid using the sync path in the case >> where the fences come from different nouveau drm devices. >> >> This works fine on a single device as the fence bo is shared >> across the devices, and mapped into each channels vma space, >> the channel offsets are therefore okay to pass between sides, >> so one channel can sync on the seqnos from the other by using >> the offset into it's vma. > > Huh, they indeed all share and map drm->fence->bo, good catch. > >> >> Signed-off-by: Dave Airlie <airlied@xxxxxxxxxx> >> Cc: stable@xxxxxxxxxxxxxxx >> --- >> drivers/gpu/drm/nouveau/nouveau_fence.c | 6 ++++-- >> 1 file changed, 4 insertions(+), 2 deletions(-) >> >> diff --git a/drivers/gpu/drm/nouveau/nouveau_fence.c b/drivers/gpu/drm/nouveau/nouveau_fence.c >> index ee5e9d40c166..a3eb1f447a29 100644 >> --- a/drivers/gpu/drm/nouveau/nouveau_fence.c >> +++ b/drivers/gpu/drm/nouveau/nouveau_fence.c >> @@ -367,11 +367,13 @@ nouveau_fence_sync(struct nouveau_bo *nvbo, struct nouveau_channel *chan, >> if (f) { >> struct nouveau_channel *prev; >> bool must_wait = true; >> + bool local; >> >> rcu_read_lock(); >> prev = rcu_dereference(f->channel); >> - if (prev && (prev == chan || >> - fctx->sync(f, prev, chan) == 0)) >> + local = prev && prev->drm == chan->drm; > > struct nouveau_channel has no pointer to a struct nouveau_drm, this should be > prev->cli->drm and chan->cli->drm instead. > > No need to resend, I can fix it when applying the patch if you want. Applied to drm-misc-fixes. > >> + if (local && (prev == chan || >> + fctx->sync(f, prev, chan) == 0)) >> must_wait = false; >> rcu_read_unlock(); >> if (!must_wait) >> -- >> 2.43.0 >>