linux-kernel - Re: [PATCH 1/2] drm/msm/dp: postpone irq_hpd event during connection pending state

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Date:   Wed, 13 Jan 2021 09:44:24 -0800
From:   khsieh@...eaurora.org
To:     Stephen Boyd <swboyd@...omium.org>
Cc:     dri-devel@...ts.freedesktop.org, robdclark@...il.com,
        sean@...rly.run, tanmay@...eaurora.org, abhinavk@...eaurora.org,
        aravindh@...eaurora.org, airlied@...ux.ie, daniel@...ll.ch,
        linux-arm-msm@...r.kernel.org, freedreno@...ts.freedesktop.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/2] drm/msm/dp: postpone irq_hpd event during connection
 pending state

On 2021-01-11 11:55, Stephen Boyd wrote:
> Quoting Kuogee Hsieh (2021-01-07 12:30:24)
>> irq_hpd event can only be executed at connected state. Therefore
>> irq_hpd event should be postponed if it happened at connection
>> pending state. This patch also make sure both link rate and lane
> 
> Why does it happen at connection pending state?
plug in need two state to complete it.
advance to connection pending state once link training completed and 
sent uevent notification to frame work.
transition to connected state after frame work provided resolution 
timing and start transmit video panel.
Therefore irq_hpd should not be handled if it occurred before connected 
state.
> 
>> are valid before start link training.
> 
> Can this part about link rate and lane being valid be split off into
> another patch?
> 
ok, i will spilt this patch into two.
I will merge irq_hpd event part into 2nd patch (drm/msm/dp: unplug 
interrupt missed after irq_hpd handler).

>> 
>> Signed-off-by: Kuogee Hsieh <khsieh@...eaurora.org>
>> ---
> 
> Any fixes tag?
> 
>>  drivers/gpu/drm/msm/dp/dp_display.c |  7 +++++++
>>  drivers/gpu/drm/msm/dp/dp_panel.c   | 12 +++++++++---
>>  2 files changed, 16 insertions(+), 3 deletions(-)
>> 
>> diff --git a/drivers/gpu/drm/msm/dp/dp_display.c 
>> b/drivers/gpu/drm/msm/dp/dp_display.c
>> index 6e971d5..3bc7ed2 100644
>> --- a/drivers/gpu/drm/msm/dp/dp_display.c
>> +++ b/drivers/gpu/drm/msm/dp/dp_display.c
>> @@ -693,6 +693,13 @@ static int dp_irq_hpd_handle(struct 
>> dp_display_private *dp, u32 data)
>>                 return 0;
>>         }
>> 
>> +       if (state == ST_CONNECT_PENDING) {
>> +               /* wait until ST_CONNECTED */
>> +               dp_add_event(dp, EV_IRQ_HPD_INT, 0, 1); /* delay = 1 
>> */
>> +               mutex_unlock(&dp->event_mutex);
>> +               return 0;
>> +       }
>> +
>>         ret = dp_display_usbpd_attention_cb(&dp->pdev->dev);
>>         if (ret == -ECONNRESET) { /* cable unplugged */
>>                 dp->core_initialized = false;