linux-kernel - Re: [PATCH v2] drm/msm/dp: do not complete dp_aux_cmd_fifo

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Date:   Thu, 15 Dec 2022 23:15:53 +0200
From:   Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
To:     Stephen Boyd <swboyd@...omium.org>,
        Kuogee Hsieh <quic_khsieh@...cinc.com>, agross@...nel.org,
        airlied@...il.com, andersson@...nel.org, daniel@...ll.ch,
        dianders@...omium.org, robdclark@...il.com, sean@...rly.run,
        vkoul@...nel.org
Cc:     quic_abhinavk@...cinc.com, quic_sbillaka@...cinc.com,
        freedreno@...ts.freedesktop.org, dri-devel@...ts.freedesktop.org,
        linux-arm-msm@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2] drm/msm/dp: do not complete dp_aux_cmd_fifo_tx() if
 irq is not for aux transfer

On 15/12/2022 22:10, Stephen Boyd wrote:
> Quoting Dmitry Baryshkov (2022-12-15 10:46:42)
>> On 15/12/2022 20:32, Kuogee Hsieh wrote:
>>>        if (!aux->cmd_busy)
>>>                return;
>>>
>>>        if (aux->native)
>>> -             dp_aux_native_handler(aux, isr);
>>> +             ret = dp_aux_native_handler(aux, isr);
>>>        else
>>> -             dp_aux_i2c_handler(aux, isr);
>>> +             ret = dp_aux_i2c_handler(aux, isr);
>>>
>>> -     complete(&aux->comp);
>>> +     if (ret == IRQ_HANDLED)
>>> +             complete(&aux->comp);
>>
>> Can you just move the complete() into the individual handling functions?
>> Then you won't have to return the error code from dp_aux_*_handler() at
>> all. You can check `isr' in that function and call complete if there was
>> any error.
> 
> I'd prefer we apply my patch and pass the irqreturn_t variable to the
> caller of this function so spurious irqs are shutdown. Should I send it
> as a proper patch?

I'm for handling the spurious IRQs in a proper way. However I believe 
that it's not related to the issue Kuogee is trying to fix.

Thus I think we should have two separate patches: one fixing the EDID 
corruption issue (for which the proper fix is !isr check, IIUC) and the 
irqreturn_t. And for the irqreturn_t it might be beneficial to move 
complete() call to the dp_aux_foo_handler(). Or might be not. That would 
depend on the patch itself.


-- 
With best wishes
Dmitry