[Intel-gfx] [CI 1/5] igt/gem_workarounds: Read the workaround registers from the active context

[Chris Wilson]

Quoting Mika Kuoppala (2017-10-03 16:19:10)
> Chris Wilson <chris at chris-wilson.co.uk> writes:
> 
> > The workarounds are only valid whilst the GPU is active. To be sure we
> > are reading the registers in the right state, issue the reads from the GPU.
> >
> 
> Yay, this is the right way :)
> 
> Some comments and findings below...
> 
> > v2: Show ignored write-only failures as debug.
> >
> > Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> > ---
> >  tests/gem_workarounds.c | 147 ++++++++++++++++++++++++++----------------------
> >  1 file changed, 81 insertions(+), 66 deletions(-)
> >
> > diff --git a/tests/gem_workarounds.c b/tests/gem_workarounds.c
> > index 5e30a7b8..95ec250a 100644
> > --- a/tests/gem_workarounds.c
> > +++ b/tests/gem_workarounds.c
> > @@ -61,20 +61,6 @@ static struct write_only_list {
> >  static struct intel_wa_reg *wa_regs;
> >  static int num_wa_regs;
> >  
> > -static void wait_gpu(void)
> > -{
> > -     int fd = drm_open_driver(DRIVER_INTEL);
> > -     gem_quiescent_gpu(fd);
> > -     close(fd);
> > -}
> > -
> > -static void test_hang_gpu(void)
> > -{
> > -     int fd = drm_open_driver(DRIVER_INTEL);
> > -     igt_post_hang_ring(fd, igt_hang_ring(fd, I915_EXEC_DEFAULT));
> > -     close(fd);
> > -}
> > -
> >  static void test_suspend_resume(void)
> >  {
> >       igt_info("Suspending the device ...\n");
> > @@ -96,49 +82,95 @@ static bool write_only(const uint32_t addr)
> >       return false;
> >  }
> >  
> > -static int workaround_fail_count(void)
> > -{
> > -     int i, fail_count = 0;
> > -
> > -     /* There is a small delay after coming ot of rc6 to the correct
> > -        render context values will get loaded by hardware (bdw,chv).
> > -        This here ensures that we have the correct context loaded before
> > -        we start to read values */
> > -     wait_gpu();
> > +#define MI_STORE_REGISTER_MEM (0x24 << 23)
> >  
> > -     igt_debug("Address    val        mask        read        result\n");
> > +static int workaround_fail_count(int fd)
> > +{
> > +     struct drm_i915_gem_exec_object2 obj[2];
> > +     struct drm_i915_gem_relocation_entry *reloc;
> > +     struct drm_i915_gem_execbuffer2 execbuf;
> > +     uint32_t result_sz, batch_sz;
> > +     uint32_t *base, *out;
> > +     int fail_count = 0;
> > +
> > +     reloc = calloc(num_wa_regs, sizeof(*reloc));
> > +     igt_assert(reloc);
> > +
> > +     result_sz = 4 * num_wa_regs;
> > +     result_sz = (result_sz + 4095) & -4096;
> 
> Macro for align?

I never remember if we have PAGE_ALIGN() or not. Quicker to write than
grep.

> Further, why do even need it. For
> what I can gather, the mapping should work for smaller
> objects also.

Our mmap interfaces we like to operate on pages and tend to complain for
some interfaces if not, or not whole object. So it is just simpler to
think in pages and not worry about which work on less.

> > -static void check_workarounds(enum operation op)
> > +static void check_workarounds(int fd, enum operation op)
> >  {
> > -     igt_assert_eq(workaround_fail_count(), 0);
> > +     igt_assert_eq(workaround_fail_count(fd), 0);
> >  
> >       switch (op) {
> >       case GPU_RESET:
> > -             test_hang_gpu();
> > +             igt_force_gpu_reset(fd);
> 
> My kbl fails with the tests as you need some mechanism
> to wait that the reset really did happen?

It waits for the reset to complete (double checked, otherwise we have a
number of nasty races around).

> Hmm the kernel should ensure that the next reading batch
> is post reset and everything should be fine.
> 
> (gem_workarounds:7286) WARNING: 0x024D0 0x00002248      0xFFFFFFFF      0x00002094      FAIL
> (gem_workarounds:7286) WARNING: 0x024D4 0x00002580      0xFFFFFFFF      0x00002094      FAIL
> (gem_workarounds:7286) WARNING: 0x024D8 0x00007304      0xFFFFFFFF      0x00002094      FAIL

These are RING_FORCE_TO_NONPRIV, hence the thread about moving them from
the WA_WRITE to I915_WRITE as they are not part of the context image.

https://patchwork.freedesktop.org/series/31099/
-Chris