linux-kernel - Re: [PATCH] drm/msm/a6xx: don't try to set GPU frequency when GMU is suspended

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Date:   Fri, 22 May 2020 16:11:59 -0600
From:   Jordan Crouse <jcrouse@...eaurora.org>
To:     Jonathan Marek <jonathan@...ek.ca>
Cc:     freedreno@...ts.freedesktop.org, Rob Clark <robdclark@...il.com>,
        Sean Paul <sean@...rly.run>, David Airlie <airlied@...ux.ie>,
        Daniel Vetter <daniel@...ll.ch>,
        "Michael J. Ruhl" <michael.j.ruhl@...el.com>,
        Sharat Masetty <smasetty@...eaurora.org>,
        "open list:DRM DRIVER FOR MSM ADRENO GPU" 
        <linux-arm-msm@...r.kernel.org>,
        "open list:DRM DRIVER FOR MSM ADRENO GPU" 
        <dri-devel@...ts.freedesktop.org>,
        open list <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] drm/msm/a6xx: don't try to set GPU frequency when GMU is
 suspended

On Mon, May 18, 2020 at 11:07:33PM -0400, Jonathan Marek wrote:
> This fixes changing the frequency in sysfs while suspended, for example
> when doing something like this:
> 
> cat devfreq/3d00000.gpu/max_freq > devfreq/3d00000.gpu/min_freq

A patch landed to fix this [1] but it crossed paths in the night with the
a640/a650 support. Can you respin this to move the pm_runtime_get_if_in_use()
check in _a6xx_gmu_set_freq() to the higher level function and then we should
be covered.

Thanks,
Jordan

[1] https://patchwork.freedesktop.org/patch/364089/?series=76829&rev=3

> Signed-off-by: Jonathan Marek <jonathan@...ek.ca>
> ---
>  drivers/gpu/drm/msm/adreno/a6xx_gmu.c | 11 +++++++++--
>  1 file changed, 9 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/msm/adreno/a6xx_gmu.c b/drivers/gpu/drm/msm/adreno/a6xx_gmu.c
> index aec54cde8534..9498803dcad9 100644
> --- a/drivers/gpu/drm/msm/adreno/a6xx_gmu.c
> +++ b/drivers/gpu/drm/msm/adreno/a6xx_gmu.c
> @@ -151,13 +151,20 @@ void a6xx_gmu_set_freq(struct msm_gpu *gpu, unsigned long freq)
>  			break;
>  
>  	gmu->current_perf_index = perf_index;
> +	gmu->freq = gmu->gpu_freqs[perf_index];
> +
> +	/*
> +	 * devfreq may try to change frequency target even when suspended
> +	 * this can happen when changing frequency through sysfs
> +	 * don't try to set freq when suspended, it will be set on resume
> +	 */
> +	if (!pm_runtime_active(gmu->dev))
> +		return;
>  
>  	if (gmu->legacy)
>  		__a6xx_gmu_set_freq(gmu, perf_index);
>  	else
>  		a6xx_hfi_set_freq(gmu, perf_index);
> -
> -	gmu->freq = gmu->gpu_freqs[perf_index];
>  }
>  
>  unsigned long a6xx_gmu_get_freq(struct msm_gpu *gpu)
> -- 
> 2.26.1
> 

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