[Intel-gfx] [PATCH 7/7] Revert "drm/i915: Enable semaphores on BDW"

[Rodrigo Vivi]

The rest of the series was a reference for the records of what I had and
let semaphores on bdw a bit more stable. But even with them we still get
hungs so please consider only to get the revert for now.


On Mon, Aug 4, 2014 at 11:15 AM, Rodrigo Vivi <rodrigo.vivi at intel.com>
wrote:

> This reverts commit 521e62e49a42661a4ee0102644517dbe2f100a23.
>
> Although POST_SYNC brought a bit of stability to Semaphores on BDW
> it didn't solved all issues and some hungs can still occour when
> semaphores are enabled on BDW. Also some sloweness can be found on some
> igt tests, althoguth it apparently doesn't affect real workloads.
>
> Besides that, no real performance gain was found on our tests with
> different
> and even multiple workloads.
>
> Let's disable it again for now. At least until we are sure it is safe
> to re-enable it.
>
> Signed-off-by: Rodrigo Vivi <rodrigo.vivi at intel.com>
> ---
>  drivers/gpu/drm/i915/i915_drv.c | 4 ++++
>  1 file changed, 4 insertions(+)
>
> diff --git a/drivers/gpu/drm/i915/i915_drv.c
> b/drivers/gpu/drm/i915/i915_drv.c
> index 6c4b25c..ec96f9a 100644
> --- a/drivers/gpu/drm/i915/i915_drv.c
> +++ b/drivers/gpu/drm/i915/i915_drv.c
> @@ -481,6 +481,10 @@ bool i915_semaphore_is_enabled(struct drm_device *dev)
>         if (i915.semaphores >= 0)
>                 return i915.semaphores;
>
> +       /* Until we get further testing... */
> +       if (IS_GEN8(dev))
> +               return false;
> +
>  #ifdef CONFIG_INTEL_IOMMU
>         /* Enable semaphores on SNB when IO remapping is off */
>         if (INTEL_INFO(dev)->gen == 6 && intel_iommu_gfx_mapped)
> --
> 1.9.3
>
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>



-- 
Rodrigo Vivi
Blog: http://blog.vivi.eng.br
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