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Message-ID: <373491a2-0fa5-0326-29cd-1650f86202d4@collabora.com>
Date:   Thu, 3 Mar 2022 10:21:46 +0100
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Subject: Re: [PATCH v1 07/10] drm/msm/adreno: Retry on gpu resume failure
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To:     Akhil P Oommen <quic_akhilpo@quicinc.com>,
        freedreno <freedreno@lists.freedesktop.org>,
        dri-devel@lists.freedesktop.org, linux-arm-msm@vger.kernel.org,
        Rob Clark <robdclark@gmail.com>,
        Dmitry Baryshkov <dmitry.baryshkov@linaro.org>,
        Bjorn Andersson <bjorn.andersson@linaro.org>
Cc:     Abhinav Kumar <quic_abhinavk@quicinc.com>,
        Daniel Vetter <daniel@ffwll.ch>,
        David Airlie <airlied@linux.ie>,
        Jonathan Marek <jonathan@marek.ca>,
        Sean Paul <sean@poorly.run>,
        Vladimir Lypak <vladimir.lypak@gmail.com>,
        linux-kernel@vger.kernel.org,
        Marijn Suijten <marijn.suijten@somainline.org>,
        Konrad Dybcio <konrad.dybcio@somainline.org>,
        Martin Botka <martin.botka@somainline.org>
References: <1646242056-2456-1-git-send-email-quic_akhilpo@quicinc.com>
 <20220302225551.v1.7.I55e39e28375b64455d1605f67453d5e91b0c2710@changeid>
From:   AngeloGioacchino Del Regno 
        <angelogioacchino.delregno@collabora.com>
In-Reply-To: <20220302225551.v1.7.I55e39e28375b64455d1605f67453d5e91b0c2710@changeid>
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Il 02/03/22 18:27, Akhil P Oommen ha scritto:
> Retry infinitely on resume failure because there is nothing much we can
> do if GPU is not ON. Also, this helps us to avoid checking for the
> return value of pm_runtime_get() to see if GPU is ON.
> 
> Signed-off-by: Akhil P Oommen <quic_akhilpo@quicinc.com>
> ---
> 
>   drivers/gpu/drm/msm/adreno/adreno_device.c | 10 +++++++++-
>   1 file changed, 9 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/msm/adreno/adreno_device.c b/drivers/gpu/drm/msm/adreno/adreno_device.c
> index 89cfd84..abcc553 100644
> --- a/drivers/gpu/drm/msm/adreno/adreno_device.c
> +++ b/drivers/gpu/drm/msm/adreno/adreno_device.c
> @@ -603,8 +603,16 @@ static const struct of_device_id dt_match[] = {
>   static int adreno_resume(struct device *dev)
>   {
>   	struct msm_gpu *gpu = dev_to_gpu(dev);
> +	int ret;
> +
> +	/* What hope do we have for the future if we can't turn ON gpu */

Hello Akhil,

the hope for the future would be to at least not lock up everything with
an infinite loop, so, please change this to have a limited amount of retries.

My guess would be that a maximum of 10 is already a lot of retries, but
feel free to choose an appropriate number.

Regards,
Angelo

> +	while (true) {
> +		ret = gpu->funcs->pm_resume(gpu);
> +		if (!ret)
> +			break;
> +	}
>   
> -	return gpu->funcs->pm_resume(gpu);
> +	return 0;
>   }
>   
>   static int active_submits(struct msm_gpu *gpu)