linux-kernel - Re: [PATCH v1 07/10] drm/msm/adreno: Retry on gpu resume failure

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Message-ID: <b1740f38-81f2-32d3-e900-30f6e2ad970b@quicinc.com>
Date:   Sat, 5 Mar 2022 00:52:25 +0530
From:   Akhil P Oommen <quic_akhilpo@...cinc.com>
To:     AngeloGioacchino Del Regno 
        <angelogioacchino.delregno@...labora.com>,
        freedreno <freedreno@...ts.freedesktop.org>,
        <dri-devel@...ts.freedesktop.org>, <linux-arm-msm@...r.kernel.org>,
        Rob Clark <robdclark@...il.com>,
        Dmitry Baryshkov <dmitry.baryshkov@...aro.org>,
        "Bjorn Andersson" <bjorn.andersson@...aro.org>
CC:     Abhinav Kumar <quic_abhinavk@...cinc.com>,
        Daniel Vetter <daniel@...ll.ch>,
        David Airlie <airlied@...ux.ie>,
        Jonathan Marek <jonathan@...ek.ca>,
        Sean Paul <sean@...rly.run>,
        Vladimir Lypak <vladimir.lypak@...il.com>,
        <linux-kernel@...r.kernel.org>,
        Marijn Suijten <marijn.suijten@...ainline.org>,
        Konrad Dybcio <konrad.dybcio@...ainline.org>,
        Martin Botka <martin.botka@...ainline.org>
Subject: Re: [PATCH v1 07/10] drm/msm/adreno: Retry on gpu resume failure

On 3/3/2022 2:51 PM, AngeloGioacchino Del Regno wrote:
> 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@...cinc.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.

Thanks for the feedback, Angelo. I will revisit this.

-Akhil.
>
> 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)
>
>