On Wed, 18 Jan 2012 11:17:52 +0000, Chris Wilson <ch...@chris-wilson.co.uk> wrote: > On Wed, 18 Jan 2012 01:24:26 +0100, Daniel Vetter <dan...@ffwll.ch> wrote: > > On Wed, Jan 18, 2012 at 01:16:02AM +0100, CC wrote: > > > I attached the error state. > > > > Nice one, your gpu seems to have simply disappeared. And the ringbuffer > > contains a rather peculiar cmd sequence. Putting Chris (maybe he > > recognizes the pattern) and Ben (he's got a patch in the works to dump a > > debug register that might be interesting here) on cc. It's too late atm > > for me to think about this some more. > > Not simply disappeared, someone clobbered it with an extremely large > hammer. The GPU was killed by a stray write to address 0 which took out > the render ring buffer and its hws page. So my first thought is a > missing relocation, and i965g springs to mind. > -Chris
At one point there was a bug in Mesa that wrote to 0:
commit dfada714f8db3deea2fea3583c3c166a78db1117
Author: Eric Anholt <e...@anholt.net>
Date: Fri Jun 17 18:20:36 2011 -0700
i965/gen6: Use an BO instead of writing to address 0 for PIPE_CONTROL W/A.
This was spectacularly unsafe. On my system, address 0 happens to be
the hardware status page for the render ring, and the first quadword
of that happens to contain nothing we ever look at, but I sure didn't
look forward to having to debug some day when, for example, the kernel
happened to bind the ringbuffer before binding the hwsp.
pgpD19f5nOl8a.pgp
Description: PGP signature
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