On 22 October 2014 17:05, Chris Wilson <chris at chris-wilson.co.uk> wrote: > On Wed, Oct 22, 2014 at 09:09:43AM +1000, Dave Airlie wrote: >> On 21 October 2014 23:38, Daniel Vetter <daniel.vetter at ffwll.ch> wrote: >> > Hi Dave, >> > >> > drm-intel-next-2014-10-03: >> > - first batch of skl stage 1 enabling >> > - fixes from Rodrigo to the PSR, fbc and sink crc code >> > - kerneldoc for the frontbuffer tracking code, runtime pm code and the >> > basic >> > interrupt enable/disable functions >> > - smaller stuff all over >> > drm-intel-next-2014-09-19: >> > - bunch more i830M fixes from Ville >> > - full ppgtt now again enabled by default >> > - more ppgtt fixes from Michel Thierry and Chris Wilson >> > - plane config work from Gustavo Padovan >> > - spinlock clarifications >> > - piles of smaller improvements all over, as usual >> >> Chris made some noises about PPGTT being broken somewhere on irc last week, >> >> Chris, did you figure that out? > > Nope. All full-ppgtt platforms (ivb/byt/hsw) suffer from spontaneously > loosing track of the right page directories and end up executing > garbage. It correlates with load, so frequently makes igt (and a few > tests in particular) die, along with piglit, webgl conformance, > benchmarking and even eventually light loads on composited desktops. > > I've made the pd uncached, added copious flushing, forced switch_mm > every time, added noops, cacheline alignment, srm, forced the execution > of batches to be synchronous, and yet IPEHR != *ACTHD. The register and > command state looks valid. The gpu resets ok and runs fine until the > error strikes again. > > [So I need to test whether switch_mm(aliasing_ppgtt) on every batch fails > as well, and whether i915.enable_rc6=0 masks it. There is the worrying > bits in bspec that talk of non-RCS as being part of the render context > state, but only the RCS pd registers are shown in the context diagrams. > I guess I should inspect the context state and see if I can spot the other > registers. If context restore (and with rc6 that could happen at any time) > switched the pd on the other rings, that would be a nice snafu.] > > I would suggest that full-ppgtt be disabled unless someone else has had > better luck finding a hsd or figuring out the missing magic. > -Chris
Thanks Chris for the report, Daniel, fill in the swear words where you like, but yeah don't think I want to pull this in this state. Either pull the enable ppgtt patch or revert it on top, Thanks, Dave.
