On Mon, Apr 24, 2017 at 03:29:48PM +0300, Mika Kuoppala wrote: > Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> writes: > > > If we poison the request before we emit commands, it should be easier to > > spot when we execute an uninitialised request. > > > > References: https://bugs.freedesktop.org/show_bug.cgi?id=100144 > > Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> > > --- > > drivers/gpu/drm/i915/intel_ringbuffer.c | 1 + > > 1 file changed, 1 insertion(+) > > > > diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c > > index 8c874996c617..1ec98851a621 100644 > > --- a/drivers/gpu/drm/i915/intel_ringbuffer.c > > +++ b/drivers/gpu/drm/i915/intel_ringbuffer.c > > @@ -1693,6 +1693,7 @@ u32 *intel_ring_begin(struct drm_i915_gem_request *req, int num_dwords) > > > > GEM_BUG_ON(ring->emit > ring->size - bytes); > > cs = ring->vaddr + ring->emit; > > + GEM_DEBUG_EXEC(memset(cs, POISON_INUSE, bytes)); > > Will more modern hardware just skipover these? If so > then perhaps more advanced solution would be to fill with bb > start into the previous address to get a guaranteed > hang on the spot. It's not so much the expectation that the value will cause a hang, but that the value is much more recognisable when diagnosing after something goes wrong. Such as we do write a complete LRI but forget the value, the command is correct and so no harm caused, but we may spot the poison later on. -Chris -- Chris Wilson, Intel Open Source Technology Centre _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/intel-gfx
