[Intel-gfx] [PATCH 2/5] drm/i915: Undo rmw damage to gen3 error interrupt handler

[Govindapillai, Vinod]

Hello

Reviewed-by: Vinod Govindapillai <vinod.govindapillai at intel.com>

BR
Vinod

On Wed, 2023-01-25 at 20:52 +0200, Ville Syrjala wrote:
> From: Ville Syrjälä <ville.syrjala at linux.intel.com>
> 
> The gen2/gen3 irq code is supposed to be identical apart
> from the 32bit vs. 16bit access width. The recent change
> to intel_de_rmw() ruined that symmetry. Restore it to avoid
> needless mental gymnastics when comparing the two codepaths.
> 
> And while at it remove the extra eir!=0 check that somehow
> ended up in the gen2 codepath only.
> 
> Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
> ---
>  drivers/gpu/drm/i915/i915_irq.c | 10 +++++-----
>  1 file changed, 5 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
> index 240d5e198904..b45d426a5bd5 100644
> --- a/drivers/gpu/drm/i915/i915_irq.c
> +++ b/drivers/gpu/drm/i915/i915_irq.c
> @@ -3510,9 +3510,7 @@ static void i8xx_error_irq_ack(struct drm_i915_private *i915,
>         u16 emr;
>  
>         *eir = intel_uncore_read16(uncore, EIR);
> -
> -       if (*eir)
> -               intel_uncore_write16(uncore, EIR, *eir);
> +       intel_uncore_write16(uncore, EIR, *eir);
>  
>         *eir_stuck = intel_uncore_read16(uncore, EIR);
>         if (*eir_stuck == 0)
> @@ -3548,7 +3546,8 @@ static void i9xx_error_irq_ack(struct drm_i915_private *dev_priv,
>  {
>         u32 emr;
>  
> -       *eir = intel_uncore_rmw(&dev_priv->uncore, EIR, 0, 0);
> +       *eir = intel_uncore_read(&dev_priv->uncore, EIR);
> +       intel_uncore_write(&dev_priv->uncore, EIR, *eir);
>  
>         *eir_stuck = intel_uncore_read(&dev_priv->uncore, EIR);
>         if (*eir_stuck == 0)
> @@ -3564,7 +3563,8 @@ static void i9xx_error_irq_ack(struct drm_i915_private *dev_priv,
>          * (or by a GPU reset) so we mask any bit that
>          * remains set.
>          */
> -       emr = intel_uncore_rmw(&dev_priv->uncore, EMR, ~0, 0xffffffff);
> +       emr = intel_uncore_read(&dev_priv->uncore, EMR);
> +       intel_uncore_write(&dev_priv->uncore, EMR, 0xffffffff);
>         intel_uncore_write(&dev_priv->uncore, EMR, emr | *eir_stuck);
>  }
>