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Date:   Wed, 13 Jan 2021 09:48:25 -0800
From:   khsieh@codeaurora.org
To:     Stephen Boyd <swboyd@chromium.org>
Cc:     dri-devel@lists.freedesktop.org, robdclark@gmail.com,
        sean@poorly.run, tanmay@codeaurora.org, abhinavk@codeaurora.org,
        aravindh@codeaurora.org, airlied@linux.ie, daniel@ffwll.ch,
        linux-arm-msm@vger.kernel.org, freedreno@lists.freedesktop.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/2] drm/msm/dp: unplug interrupt missed after irq_hpd
 handler
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On 2021-01-11 11:54, Stephen Boyd wrote:
> Quoting Kuogee Hsieh (2021-01-07 12:30:25)
>> There is HPD unplug interrupts missed at scenario of an irq_hpd
>> followed by unplug interrupts with around 10 ms in between.
>> Since both AUX_SW_RESET and DP_SW_RESET clear pending HPD interrupts,
>> irq_hpd handler should not issues either aux or sw reset to avoid
>> following unplug interrupt be cleared accidentally.
> 
> So the problem is that we're resetting the DP aux phy in the middle of
> the HPD state machine transitioning states?
> 
yes, after reset aux, hw clear pending hpd interrupts
>> 
>> Signed-off-by: Kuogee Hsieh <khsieh@codeaurora.org>
>> ---
>> diff --git a/drivers/gpu/drm/msm/dp/dp_catalog.c 
>> b/drivers/gpu/drm/msm/dp/dp_catalog.c
>> index 44f0c57..9c0ce98 100644
>> --- a/drivers/gpu/drm/msm/dp/dp_catalog.c
>> +++ b/drivers/gpu/drm/msm/dp/dp_catalog.c
>> @@ -190,6 +190,18 @@ int dp_catalog_aux_clear_hw_interrupts(struct 
>> dp_catalog *dp_catalog)
>>         return 0;
>>  }
>> 
>> +/**
>> + * dp_catalog_aux_reset() - reset AUX controller
>> + *
>> + * @aux: DP catalog structure
>> + *
>> + * return: void
>> + *
>> + * This function reset AUX controller
>> + *
>> + * NOTE: reset AUX controller will also clear any pending HPD related 
>> interrupts
>> + *
>> + */
>>  void dp_catalog_aux_reset(struct dp_catalog *dp_catalog)
>>  {
>>         u32 aux_ctrl;
>> @@ -483,6 +495,18 @@ int dp_catalog_ctrl_set_pattern(struct dp_catalog 
>> *dp_catalog,
>>         return 0;
>>  }
>> 
>> +/**
>> + * dp_catalog_ctrl_reset() - reset DP controller
>> + *
>> + * @aux: DP catalog structure
> 
> It's called dp_catalog though.
registers access are through dp_catalog_xxxx
> 
>> + *
>> + * return: void
>> + *
>> + * This function reset DP controller
> 
> resets the
> 
>> + *
>> + * NOTE: reset DP controller will also clear any pending HPD related 
>> interrupts
>> + *
>> + */
>>  void dp_catalog_ctrl_reset(struct dp_catalog *dp_catalog)
>>  {
>>         u32 sw_reset;
>> diff --git a/drivers/gpu/drm/msm/dp/dp_ctrl.c 
>> b/drivers/gpu/drm/msm/dp/dp_ctrl.c
>> index e3462f5..f96c415 100644
>> --- a/drivers/gpu/drm/msm/dp/dp_ctrl.c
>> +++ b/drivers/gpu/drm/msm/dp/dp_ctrl.c
>> @@ -1296,7 +1296,8 @@ static int dp_ctrl_setup_main_link(struct 
>> dp_ctrl_private *ctrl,
>>          * transitioned to PUSH_IDLE. In order to start transmitting
>>          * a link training pattern, we have to first do soft reset.
>>          */
>> -       dp_catalog_ctrl_reset(ctrl->catalog);
>> +       if (*training_step != DP_TRAINING_NONE)
> 
> Can we check for the positive value instead? i.e.
> DP_TRAINING_1/DP_TRAINING_2
> 
>> +               dp_catalog_ctrl_reset(ctrl->catalog);
>> 
>>         ret = dp_ctrl_link_train(ctrl, cr, training_step);
>>