linux-kernel - Re: [PATCH v2] drm/msm/dp: handle irq_hpd with sink

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Date:   Wed, 12 May 2021 16:30:57 -0700
From:   khsieh@...eaurora.org
To:     Stephen Boyd <swboyd@...omium.org>
Cc:     agross@...nel.org, bjorn.andersson@...aro.org, robdclark@...il.com,
        sean@...rly.run, vkoul@...nel.org, abhinavk@...eaurora.org,
        aravindh@...eaurora.org, linux-arm-msm@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2] drm/msm/dp: handle irq_hpd with sink_count = 0
 correctly

On 2021-05-12 11:50, Stephen Boyd wrote:
> Quoting Kuogee Hsieh (2021-05-12 10:29:18)
>> irq_hpd interrupt should be handled after dongle plugged in and
>> before dongle unplugged. Hence irq_hpd interrupt is enabled at
>> the end of the plugin handle and disabled at the beginning of
>> unplugged handle. Current irq_hpd with sink_count = 0 is wrongly
>> handled same as the dongle unplugged which tears down the mainlink
>> and disables the phy. This patch fixes this problem by only tearing
>> down the mainlink but keeping phy enabled at irq_hpd with
>> sink_count = 0 handle so that next irq_hpe with sink_count =1 can be
>> handled by setup mainlink only.
>> 
>> Changes in v2:
>> -- add ctrl->phy_Power_count
>> 
>> Signed-off-by: Kuogee Hsieh <khsieh@...eaurora.org>
>> ---
>>  drivers/gpu/drm/msm/dp/dp_catalog.c |  5 +--
>>  drivers/gpu/drm/msm/dp/dp_ctrl.c    | 83 
>> ++++++++++++++++++++++++++++++++++---
>>  drivers/gpu/drm/msm/dp/dp_ctrl.h    |  2 +
>>  drivers/gpu/drm/msm/dp/dp_display.c | 46 +++++++++++++++-----
>>  4 files changed, 118 insertions(+), 18 deletions(-)
>> 
>> diff --git a/drivers/gpu/drm/msm/dp/dp_catalog.c 
>> b/drivers/gpu/drm/msm/dp/dp_catalog.c
>> index b1a9b1b..f4f53f2 100644
>> --- a/drivers/gpu/drm/msm/dp/dp_catalog.c
>> +++ b/drivers/gpu/drm/msm/dp/dp_catalog.c
>> @@ -582,10 +582,9 @@ void dp_catalog_ctrl_hpd_config(struct dp_catalog 
>> *dp_catalog)
>> 
>>         u32 reftimer = dp_read_aux(catalog, REG_DP_DP_HPD_REFTIMER);
>> 
>> -       /* enable HPD interrupts */
>> +       /* enable HPD plug and unplug interrupts */
>>         dp_catalog_hpd_config_intr(dp_catalog,
>> -               DP_DP_HPD_PLUG_INT_MASK | DP_DP_IRQ_HPD_INT_MASK
>> -               | DP_DP_HPD_UNPLUG_INT_MASK | 
>> DP_DP_HPD_REPLUG_INT_MASK, true);
>> +               DP_DP_HPD_PLUG_INT_MASK | DP_DP_HPD_UNPLUG_INT_MASK, 
>> true);
>> 
>>         /* Configure REFTIMER and enable it */
>>         reftimer |= DP_DP_HPD_REFTIMER_ENABLE;
>> diff --git a/drivers/gpu/drm/msm/dp/dp_ctrl.c 
>> b/drivers/gpu/drm/msm/dp/dp_ctrl.c
>> index 8d59eb9..b5bed5f 100644
>> --- a/drivers/gpu/drm/msm/dp/dp_ctrl.c
>> +++ b/drivers/gpu/drm/msm/dp/dp_ctrl.c
>> @@ -77,6 +77,8 @@ struct dp_ctrl_private {
>>         struct dp_parser *parser;
>>         struct dp_catalog *catalog;
>> 
>> +       int phy_power_count;
> 
> This is still redundant. Please restructure the code to call the power
> on/off function in one place and the init/exit function in another so
> that we don't have to reference count it.

ok, v3 patch uploaded