linux-kernel - Re: [PATCH v4 15/38] drm/bridge: analogix_dp: Ensure edp is disabled when shutting down the panel

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Message-ID: <4d0e97f2-985c-fe04-9390-45ea60f3d731@collabora.com>
Date:   Tue, 6 Mar 2018 09:49:45 +0100
From:   Enric Balletbo i Serra <enric.balletbo@...labora.com>
To:     Marek Szyprowski <m.szyprowski@...sung.com>,
        architt@...eaurora.org, inki.dae@...sung.com,
        thierry.reding@...il.com, hjc@...k-chips.com,
        seanpaul@...omium.org, airlied@...ux.ie, tfiga@...omium.org,
        heiko@...ech.de
Cc:     hshi@...omium.org, wzz@...k-chips.com, hl@...k-chips.com,
        linux-kernel@...r.kernel.org, dri-devel@...ts.freedesktop.org,
        dianders@...omium.org, linux-rockchip@...ts.infradead.org,
        orjan.eide@....com,
        Stéphane Marchesin <marcheu@...omium.org>
Subject: Re: [PATCH v4 15/38] drm/bridge: analogix_dp: Ensure edp is disabled
 when shutting down the panel

Hi Marek,

On 06/03/18 08:35, Marek Szyprowski wrote:
> Hi All,
> 
> This is the patch, which introduces the issue I've pointed here:
> 
> https://lists.freedesktop.org/archives/dri-devel/2018-March/167794.html
> 
> On 2018-03-05 23:23, Enric Balletbo i Serra wrote:
>> From: Lin Huang <hl@...k-chips.com>
>>
>> When panel is shut down, we should make sure edp can be disabled to avoid
>> undefined behavior.
>>
>> Cc: Stéphane Marchesin <marcheu@...omium.org>
>> Signed-off-by: Lin Huang <hl@...k-chips.com>
>> Signed-off-by: zain wang <wzz@...k-chips.com>
>> Signed-off-by: Sean Paul <seanpaul@...omium.org>
>> Signed-off-by: Thierry Escande <thierry.escande@...labora.com>
>> Reviewed-by: Andrzej Hajda <a.hajda@...sung.com>
>> Signed-off-by: Enric Balletbo i Serra <enric.balletbo@...labora.com>
>> ---
>>
>>   drivers/gpu/drm/bridge/analogix/analogix_dp_core.c | 11 +++++++++++
>>   1 file changed, 11 insertions(+)
>>
>> diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
>> b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
>> index 92fb9a072cb6..9b7d530ad24c 100644
>> --- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
>> +++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
>> @@ -1160,6 +1160,12 @@ static int analogix_dp_set_bridge(struct
>> analogix_dp_device *dp)
>>         pm_runtime_get_sync(dp->dev);
>>   +    ret = clk_prepare_enable(dp->clock);
>> +    if (ret < 0) {
>> +        DRM_ERROR("Failed to prepare_enable the clock clk [%d]\n", ret);
>> +        goto out_dp_clk_pre;
>> +    }
>> +
>>       if (dp->plat_data->power_on)
>>           dp->plat_data->power_on(dp->plat_data);
>>   @@ -1191,6 +1197,8 @@ static int analogix_dp_set_bridge(struct
>> analogix_dp_device *dp)
>>       phy_power_off(dp->phy);
>>       if (dp->plat_data->power_off)
>>           dp->plat_data->power_off(dp->plat_data);
>> +    clk_disable_unprepare(dp->clock);
>> +out_dp_clk_pre:
>>       pm_runtime_put_sync(dp->dev);
>>         return ret;
>> @@ -1234,10 +1242,13 @@ static void analogix_dp_bridge_disable(struct
>> drm_bridge *bridge)
>>         disable_irq(dp->irq);
>>       phy_power_off(dp->phy);
>> +    analogix_dp_set_analog_power_down(dp, POWER_ALL, 1);
> 
> In case of Exynos DP, external PHY is used to power the DP block, so no
> register access should be performed after phy_power_off(). Please move
> analogix_dp_set_analog_power_down() before phy_power_off().
> 

Oh, sorry, I missed that change, I'll include in next version, but I will wait a
little bit more before send for if I receive feedback on the others patches.


>>         if (dp->plat_data->power_off)
>>           dp->plat_data->power_off(dp->plat_data);
>>   +    clk_disable_unprepare(dp->clock);
>> +
>>       pm_runtime_put_sync(dp->dev);
>>         ret = analogix_dp_prepare_panel(dp, false, true);
> 
> Best regards
Enric