Re: [Intel-gfx] [PATCH] drm/i915: Skip Bit12 fw domain reset for gen12+

[Matt Roper <matthew.d.roper@intel.com>]

On Wed, Aug 17, 2022 at 03:43:04PM -0700, Radhakrishna Sripada wrote:
> Bit12 of the Forcewake request register should not be cleared post
> gen12. Do not touch this bit while clearing during fw domain reset.
> 
> Bspec: 52542
> 
> Signed-off-by: Sushma Venkatesh Reddy <sushma.venkatesh.reddy@intel.com>
> Signed-off-by: Radhakrishna Sripada <radhakrishna.sripada@intel.com>
> ---
>  drivers/gpu/drm/i915/intel_uncore.c | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_uncore.c b/drivers/gpu/drm/i915/intel_uncore.c
> index a852c471d1b3..c85e2b686c95 100644
> --- a/drivers/gpu/drm/i915/intel_uncore.c
> +++ b/drivers/gpu/drm/i915/intel_uncore.c
> @@ -113,7 +113,10 @@ fw_domain_reset(const struct intel_uncore_forcewake_domain *d)
>  	 * off in ICL+), so no waiting for acks
>  	 */
>  	/* WaRsClearFWBitsAtReset:bdw,skl */

While we're at it, let's remove the "bdw,skl" from this comment since
it's misleading and doesn't match the code.  We do still apply this
workaround on other pre-gen12 platforms than just those two.

Aside from the comment tweak,

Reviewed-by: Matt Roper <matthew.d.roper@intel.com>

> -	fw_clear(d, 0xffff);
> +	if (GRAPHICS_VER(d->uncore->i915) >= 12)
> +		fw_clear(d, 0xefff);
> +	else
> +		fw_clear(d, 0xffff);
>  }
>  
>  static inline void
> -- 
> 2.25.1
> 

-- 
Matt Roper
Graphics Software Engineer
VTT-OSGC Platform Enablement
Intel Corporation