linux-kernel - Re: [PATCH] drm/rockchip: cdn-dp: Fix error handling

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Date:   Mon, 20 Feb 2017 07:41:16 +0100
From:   Christophe JAILLET <christophe.jaillet@...adoo.fr>
To:     Mark yao <mark.yao@...k-chips.com>, airlied@...ux.ie,
        heiko@...ech.de
Cc:     linux-rockchip@...ts.infradead.org,
        kernel-janitors@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org,
        dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] drm/rockchip: cdn-dp: Fix error handling

Le 20/02/2017 à 02:40, Mark yao a écrit :
> On 2017年02月20日 00:59, Christophe JAILLET wrote:
>> It is likely that both 'clk_disable_unprepare()' should be called if
>> 'pm_runtime_get_sync()' fails.
>>
>> Add a new label for that, because 'err_set_rate' is not meaningful in 
>> this
>> case.
>>
>>
>> Fixes: 1a0f7ed3abe2 ("drm/rockchip: cdn-dp: add cdn DP support for 
>> rk3399")
>>
>> Signed-off-by: Christophe JAILLET <christophe.jaillet@...adoo.fr>
>> ---
>> Not sure but a 'pm_runtime_get_sync()' is maybe also required in the
>> 'err_set_rate' path.
>> ---
>>   drivers/gpu/drm/rockchip/cdn-dp-core.c | 3 ++-
>>   1 file changed, 2 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/gpu/drm/rockchip/cdn-dp-core.c 
>> b/drivers/gpu/drm/rockchip/cdn-dp-core.c
>> index 9ab67a670885..0fe1ec8b8fb1 100644
>> --- a/drivers/gpu/drm/rockchip/cdn-dp-core.c
>> +++ b/drivers/gpu/drm/rockchip/cdn-dp-core.c
>> @@ -111,7 +111,7 @@ static int cdn_dp_clk_enable(struct cdn_dp_device 
>> *dp)
>>       ret = pm_runtime_get_sync(dp->dev);
>>       if (ret < 0) {
>>           DRM_DEV_ERROR(dp->dev, "cannot get pm runtime %d\n", ret);
>> -        goto err_pclk;
>> +        goto err_sync;
>
> I think the name err_pm_runtime_get is better.
> err_sync is not a clear name for the pm_runtime_get_sync.
>
I will change it.

>>       }
>>         reset_control_assert(dp->core_rst);
>> @@ -133,6 +133,7 @@ static int cdn_dp_clk_enable(struct cdn_dp_device 
>> *dp)
>>       return 0;
>>     err_set_rate:
>> +err_sync:
>
> miss pm_runtime_put, it should be:
>
I am wondering if 'pm_runtime_put_sync' should be added, instead.
We want to revert the 'pm_runtime_get_sync' of line 111. According to 
the naming of the function, the _sync version looks more logical to me.
Using ccoccinelle shows that 2/3 of functions calling both 
'pm_runtime_get_sync' and 'pm_runtime_get[_sync]' and using the _sync 
variant.

Which semantic is the correct one?


> err_set_rate:
>     pm_runtime_put(dp->dev);
> err_pm_runtime_get:
>     clk_disable_unprepare(dp->core_clk);
> err_core_clk:
>
>> clk_disable_unprepare(dp->core_clk);
>>   err_core_clk:
>>       clk_disable_unprepare(dp->pclk);
>
>