[Intel-gfx] [PATCH] drm/i915: Move the irq_barrier for reset earlier into reset_prepare

[Michel Thierry]

On 10/02/17 10:52, Chris Wilson wrote:
> When updating the bookkeeping following the reset, we need the seqno to
> be coherent on the CPU prior to trusting its result for deciding whether
> any request is completed. We need the irq_barrier before we start making
> these decisions, i.e. in reset_prepare.
>
> References: https://bugs.freedesktop.org/show_bug.cgi?id=99733
> Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> Cc: Mika Kuoppala <mika.kuoppala at intel.com>
> ---
>  drivers/gpu/drm/i915/i915_gem.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
>

I havent seen the issue in the platforms I have, but makes sense. If you 
need one,

Reviewed-by: Michel Thierry <michel.thierry at intel.com>

> diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
> index ed60d5881b40..3066f94da8f0 100644
> --- a/drivers/gpu/drm/i915/i915_gem.c
> +++ b/drivers/gpu/drm/i915/i915_gem.c
> @@ -2677,6 +2677,9 @@ int i915_gem_reset_prepare(struct drm_i915_private *dev_priv)
>                 tasklet_disable(&engine->irq_tasklet);
>                 tasklet_kill(&engine->irq_tasklet);
>
> +               if (engine->irq_seqno_barrier)
> +                       engine->irq_seqno_barrier(engine);
> +
>                 if (engine_stalled(engine)) {
>                         request = i915_gem_find_active_request(engine);
>                         if (request && request->fence.error == -EIO)
> @@ -2773,9 +2776,6 @@ static void i915_gem_reset_engine(struct intel_engine_cs *engine)
>  {
>         struct drm_i915_gem_request *request;
>
> -       if (engine->irq_seqno_barrier)
> -               engine->irq_seqno_barrier(engine);
> -
>         request = i915_gem_find_active_request(engine);
>         if (request && i915_gem_reset_request(request)) {
>                 DRM_DEBUG_DRIVER("resetting %s to restart from tail of request 0x%x\n",
> --
> 2.11.0
>
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