On Mon, Mar 27, 2017 at 01:44:00PM +0300, Mika Kuoppala wrote: > Chris Wilson <[email protected]> writes: > > > If the request->wa_tail is 0 (because it landed exactly on the end of > > the ringbuffer), when we reconstruct request->tail following a reset we > > fill in an illegal value (-8 or 0x001ffff8). As a result, RING_HEAD is > > never able to catch up with RING_TAIL and the GPU spins endlessly. If > > the ring contains a couple of breadcrumbs, even our hangcheck is unable > > to catch the busy-looping as the ACTHD and seqno continually advance. > > Tail is past ring size (on hw) and the ring contents has seqno writes. > So we will replay the ring contents over and over and seqno advances > and wraps back to the first breadcrumbs in ring?
Yup. It was most confusing to watch. The execlist_port[] was static, RING_START was static, yet the seqno kept changing. I felt like I was hallucinating. That or insomnia. -Chris -- Chris Wilson, Intel Open Source Technology Centre _______________________________________________ Intel-gfx mailing list [email protected] https://lists.freedesktop.org/mailman/listinfo/intel-gfx
