[Intel-gfx] [PATCH i-g-t] lib: don't hang on blt on snb

[Daniel Vetter]

On Mon, Aug 7, 2017 at 6:34 PM, Chris Wilson <chris at chris-wilson.co.uk> wrote:
> Quoting Daniel Vetter (2017-08-07 17:26:56)
>> On Fri, Aug 04, 2017 at 06:05:10PM +0100, Chris Wilson wrote:
>> > Quoting Daniel Vetter (2017-08-04 17:07:22)
>> > > We now have full (or a lot at least) igt running in beta CI, and snb
>> > > blt hangs are really unhappy:
>> > >
>> > > - drv_hangman at error-state-capture-blt and gem_exec_capture at capture-blt
>> > >   reliably result in insta-machine death when we try to reset the gpu,
>> > >   both on the CI snb and the one I have here.
>> > >
>> > > - Other testcases also randomly (and sometimes rather rarely) die on
>> > >   snb.
>> > >
>> > > We can't use the endless batch because that results in a reset failure
>> > > and wedged gpu, so also not really better.
>> >
>> > It shouldn't be the recursion, but the invalid instruction we use to try
>> > and trigger the hang quicker (otherwise hangcheck may see the advancing
>> > ACTHD and give us longer to escape the loop).
>> >
>> > In gem_exec_capture we shouldn't even need that invalid instruction, we
>> > just need the busy batch as we pull the trigger ourselves, and if that
>> > fails to reset a simple recursive batch we have some issues to resolve.
>>
>> Endless loop for haning results in a reset failure on blt as described in
>> the commit message. We end up with a permanent and unrecoverable -EIO,
>> which is as deadly to CI as outright killing the machine.
>
> No, it doesn't. snb-gt1 exhibiting the machine death on invalid blt
> instruction as reported, after fixes:

Well my gt2 disagreed, but I guess we can push your patches to igt and
then ask CI whether we need more.
-Daniel

>
> Subtest error-state-basic: SUCCESS (0.001s)
> Subtest error-state-capture-render: SUCCESS (7.740s)
> Subtest error-state-capture-bsd: SUCCESS (6.024s)
> Test requirement not met in function test_error_state_capture, file drv_hangman.c:187:
> Test requirement: gem_has_ring(device, ring_id)
> Subtest error-state-capture-bsd1: SKIP (0.000s)
> Test requirement not met in function test_error_state_capture, file drv_hangman.c:187:
> Test requirement: gem_has_ring(device, ring_id)
> Subtest error-state-capture-bsd2: SKIP (0.000s)
> Subtest error-state-capture-blt: SUCCESS (13.965s)
> Test requirement not met in function test_error_state_capture, file drv_hangman.c:187:
> Test requirement: gem_has_ring(device, ring_id)
> Subtest error-state-capture-vebox: SKIP (0.000s)
>
> Subtest capture-render: SUCCESS (0.003s)
> Test requirement not met in function __real_main175, file gem_exec_capture.c:202:
> Test requirement: gem_can_store_dword(fd, e->exec_id | e->flags)
> Subtest capture-bsd: SKIP (0.000s)
> Test requirement not met in function gem_require_ring, file ioctl_wrappers.c:1642:
> Test requirement: gem_has_ring(fd, ring)
> Subtest capture-bsd1: SKIP (0.000s)
> Test requirement not met in function gem_require_ring, file ioctl_wrappers.c:1642:
> Test requirement: gem_has_ring(fd, ring)
> Subtest capture-bsd2: SKIP (0.000s)
> Subtest capture-blt: SUCCESS (0.002s)
> Test requirement not met in function gem_require_ring, file ioctl_wrappers.c:1642:
> Test requirement: gem_has_ring(fd, ring)
> Subtest capture-vebox: SKIP (0.000s)
>
> -Chris



-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch