Re: [Intel-gfx] [PATCH] drm/i915/slpc: Set rps' min and max frequencies even with SLPC.

[Rodrigo Vivi <rodrigo.vivi@intel.com>]

On Thu, Aug 25, 2022 at 06:23:15PM -0400, Rodrigo Vivi wrote:
> We need to inform PCODE of a desired ring frequencies so PCODE update
> the memory frequencies to us. rps->min_freq and rps->max_freq are the
> frequencies used in that request. However they were unset when SLPC was
> enabled and PCODE never updated the memory freq.
> 
> Let's at least for now get these freq set up so we can inform PCODE.
> 
> Cc: Ashutosh Dixit <ashutosh.dixit@intel.com>
> Tested-by: Sushma Venkatesh Reddy <sushma.venkatesh.reddy@intel.com>
> Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

As suggested by Sushma:
Fixes: 7ba79a671568 ("drm/i915/guc/slpc: Gate Host RPS when SLPC is enabled")
Cc: <stable@vger.kernel.org> # v5.15+

> ---
>  drivers/gpu/drm/i915/gt/intel_rps.c | 18 +++++++++++++++++-
>  1 file changed, 17 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/i915/gt/intel_rps.c b/drivers/gpu/drm/i915/gt/intel_rps.c
> index 8c289a032103..58a82978d5df 100644
> --- a/drivers/gpu/drm/i915/gt/intel_rps.c
> +++ b/drivers/gpu/drm/i915/gt/intel_rps.c
> @@ -1128,6 +1128,20 @@ void gen6_rps_get_freq_caps(struct intel_rps *rps, struct intel_rps_freq_caps *c
>  	}
>  }
>  
> +static void rps_basic_init_for_slpc(struct intel_rps *rps)
> +{
> +	struct intel_rps_freq_caps caps;
> +
> +	/*
> +	 * Even with SLPC we need to initialize at least a basic min and max
> +	 * frequency so we can inform pcode a desired IA ring frequency in
> +	 * gen6_update_ring_freq
> +	 */
> +	gen6_rps_get_freq_caps(rps, &caps);
> +	rps->min_freq = caps.min_freq;
> +	rps->max_freq = caps.rp0_freq;
> +}
> +
>  static void gen6_rps_init(struct intel_rps *rps)
>  {
>  	struct drm_i915_private *i915 = rps_to_i915(rps);
> @@ -1970,8 +1984,10 @@ void intel_rps_init(struct intel_rps *rps)
>  {
>  	struct drm_i915_private *i915 = rps_to_i915(rps);
>  
> -	if (rps_uses_slpc(rps))
> +	if (rps_uses_slpc(rps)) {
> +		rps_basic_init_for_slpc(rps);
>  		return;
> +	}
>  
>  	if (IS_CHERRYVIEW(i915))
>  		chv_rps_init(rps);
> -- 
> 2.37.1
>