[PATCH 1/3] drm/radeon: stop poisoning the GART TLB

[Marek Olšák]

Sorry to tell you the bad news. This patch doesn't fix the hangs on my machine.

I tested drm-next-3.16 from Alex's tree. I also switched copying from
SDMA to CP DMA, which hung too.

I also tried this:

git checkout (the problematic commit):
6d2f294 - drm/radeon: use normal BOs for the page tables v4

git cherry-pick (fixes):
0e97703c - drm/radeon: add define for flags used in R600+ GTT
0986c1a5 - drm/radeon: stop poisoning the GART TLB
4906f689 - drm/radeon: fix page directory update size estimation
4b095566 - drm/radeon: fix buffer placement under memory pressure v2

Then I tested both SDMA and CP DMA copying. Both were unstable.

Testing was done with piglit / quick.tests.

Marek


On Wed, Jun 4, 2014 at 3:29 PM, Christian König <deathsimple at vodafone.de> wrote:
> From: Christian König <christian.koenig at amd.com>
>
> When we set the valid bit on invalid GART entries they are
> loaded into the TLB when an adjacent entry is loaded. This
> poisons the TLB with invalid entries which are sometimes
> not correctly removed on TLB flush.
>
> For stable inclusion the patch probably needs to be modified a bit.
>
> Signed-off-by: Christian König <christian.koenig at amd.com>
> Cc: stable at vger.kernel.org
> ---
>  drivers/gpu/drm/radeon/rs600.c | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/radeon/rs600.c b/drivers/gpu/drm/radeon/rs600.c
> index 0a8be63..e0465b2 100644
> --- a/drivers/gpu/drm/radeon/rs600.c
> +++ b/drivers/gpu/drm/radeon/rs600.c
> @@ -634,7 +634,10 @@ int rs600_gart_set_page(struct radeon_device *rdev, int i, uint64_t addr)
>                 return -EINVAL;
>         }
>         addr = addr & 0xFFFFFFFFFFFFF000ULL;
> -       addr |= R600_PTE_GART;
> +       if (addr == rdev->dummy_page.addr)
> +               addr |= R600_PTE_SYSTEM | R600_PTE_SNOOPED;
> +       else
> +               addr |= R600_PTE_GART;
>         writeq(addr, ptr + (i * 8));
>         return 0;
>  }
> --
> 1.9.1
>
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