linux-kernel - Re: [PATCH v4 5/7] drm/msm/a6xx: Ensure CX collapse during gpu recovery

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Date:   Thu, 18 Aug 2022 10:54:38 +0200
From:   Philipp Zabel <p.zabel@...gutronix.de>
To:     Akhil P Oommen <quic_akhilpo@...cinc.com>
Cc:     freedreno <freedreno@...ts.freedesktop.org>,
        dri-devel@...ts.freedesktop.org, linux-arm-msm@...r.kernel.org,
        Rob Clark <robdclark@...il.com>,
        Bjorn Andersson <bjorn.andersson@...aro.org>,
        Dmitry Baryshkov <dmitry.baryshkov@...aro.org>,
        Matthias Kaehlcke <mka@...omium.org>,
        Jonathan Marek <jonathan@...ek.ca>,
        Jordan Crouse <jordan@...micpenguin.net>,
        Douglas Anderson <dianders@...omium.org>,
        Abhinav Kumar <quic_abhinavk@...cinc.com>,
        Chia-I Wu <olvaffe@...il.com>, Daniel Vetter <daniel@...ll.ch>,
        David Airlie <airlied@...ux.ie>, Sean Paul <sean@...rly.run>,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v4 5/7] drm/msm/a6xx: Ensure CX collapse during gpu
 recovery

Hi Akhil,

On Wed, Aug 17, 2022 at 08:44:18PM +0530, Akhil P Oommen wrote:
> Because there could be transient votes from other drivers/tz/hyp which
> may keep the cx gdsc enabled, we should poll until cx gdsc collapses.
> We can use the reset framework to poll for cx gdsc collapse from gpucc
> clk driver.
> 
> This feature requires support from the platform's gpucc driver.
> 
> Signed-off-by: Akhil P Oommen <quic_akhilpo@...cinc.com>
> Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
> ---
> 
> (no changes since v3)
> 
> Changes in v3:
> - Use reset interface from gpucc driver to poll for cx gdsc collapse
>   https://patchwork.freedesktop.org/series/106860/
> 
>  drivers/gpu/drm/msm/adreno/a6xx_gpu.c | 4 ++++
>  drivers/gpu/drm/msm/msm_gpu.c         | 4 ++++
>  drivers/gpu/drm/msm/msm_gpu.h         | 4 ++++
>  3 files changed, 12 insertions(+)
> 
[...]
> diff --git a/drivers/gpu/drm/msm/msm_gpu.c b/drivers/gpu/drm/msm/msm_gpu.c
> index 07e55a6..4a57627 100644
> --- a/drivers/gpu/drm/msm/msm_gpu.c
> +++ b/drivers/gpu/drm/msm/msm_gpu.c
[...]
> @@ -903,6 +904,9 @@ int msm_gpu_init(struct drm_device *drm, struct platform_device *pdev,
>  	if (IS_ERR(gpu->gpu_cx))
>  		gpu->gpu_cx = NULL;
>  
> +	gpu->cx_collapse = devm_reset_control_get_optional(&pdev->dev,
> +			"cx_collapse");

Please use devm_reset_control_get_optional_exclusive() instead.

With that,
Reviewed-by: Philipp Zabel <p.zabel@...gutronix.de>

regards
Philipp