On 7/19/22 11:54, Paul Kocialkowski wrote:
> Hi Hans,
>
> On Mon 18 Jul 22, 18:08, Hans Verkuil wrote:
>> Both sun6i_mipi_csi2.c and sun8i_a83t_mipi_csi2.c have the same issue:
>> the comment before the ret = 0 assignment is incorrect, drop it and
>> always assign the result of the v4l2_subdev_call(..., 0) to ret.
>
> Not sure what is incorrect about it. I agree that it's good to return the
> return code of v4l2_subdev_call instead of always 0 on the !on path though.
>
>> In the disable label check for !on and set ret to 0 in that case.
>>
>> This fixes two smatch warnings:
>>
>> drivers/media/platform/sunxi/sun6i-mipi-csi2/sun6i_mipi_csi2.c:193 sun6i_mipi_csi2_s_stream() warn: missing error code 'ret'
>
> I don't think this is legit: the initialization of ret is specifically there
> to avoid an undefined ret there.
I believe so as well, but I need to get rid of the smatch warning.
>
>> drivers/media/platform/sunxi/sun8i-a83t-mipi-csi2/sun8i_a83t_mipi_csi2.c:225 sun8i_a83t_mipi_csi2_s_stream() warn: missing error code 'ret'
>>
>> Signed-off-by: Hans Verkuil <hverkuil-cisco@xxxxxxxxx>
>> ---
>> .../media/platform/sunxi/sun6i-mipi-csi2/sun6i_mipi_csi2.c | 7 ++++---
>> .../sunxi/sun8i-a83t-mipi-csi2/sun8i_a83t_mipi_csi2.c | 7 ++++---
>> 2 files changed, 8 insertions(+), 6 deletions(-)
>>
>> diff --git a/drivers/media/platform/sunxi/sun6i-mipi-csi2/sun6i_mipi_csi2.c b/drivers/media/platform/sunxi/sun6i-mipi-csi2/sun6i_mipi_csi2.c
>> index 31e12f1506cb..a4e3f9a6b2ff 100644
>> --- a/drivers/media/platform/sunxi/sun6i-mipi-csi2/sun6i_mipi_csi2.c
>> +++ b/drivers/media/platform/sunxi/sun6i-mipi-csi2/sun6i_mipi_csi2.c
>> @@ -182,14 +182,13 @@ static int sun6i_mipi_csi2_s_stream(struct v4l2_subdev *subdev, int on)
>> unsigned int lanes_count =
>> csi2_dev->bridge.endpoint.bus.mipi_csi2.num_data_lanes;
>> unsigned long pixel_rate;
>> - /* Initialize to 0 to use both in disable label (ret != 0) and off. */
>> - int ret = 0;
>> + int ret;
>>
>> if (!source_subdev)
>> return -ENODEV;
>>
>> if (!on) {
>> - v4l2_subdev_call(source_subdev, video, s_stream, 0);
>> + ret = v4l2_subdev_call(source_subdev, video, s_stream, 0);
>> goto disable;
>> }
>>
>> @@ -281,6 +280,8 @@ static int sun6i_mipi_csi2_s_stream(struct v4l2_subdev *subdev, int on)
>> return 0;
>>
>> disable:
>> + if (!on)
>> + ret = 0;
>
> Then this will always overwrite the ret value from v4l2_subdev_call with the
> !on disable path. Looks like this can be removed.
Returning an error when stopping streaming is kind of pointless, since
what are you going to do with that error?
I assumed that's why the original code did this, and I didn't want to
change the behavior.
If you think it is better to just return the error, then that can be a
patch on top.
BTW, I think it would have been better to have separate streamon and streamoff
ops instead of a single s_stream. Starting streaming would return an int, while
stopping streaming would be a void function. In general when you stop, release,
close, etc. something there is no point in an error code since there is nothing
you can do with it.
Regards,
Hans
>
> What do you think?
>
> Paul
>
>> phy_power_off(dphy);
>> sun6i_mipi_csi2_disable(csi2_dev);
>>
>> diff --git a/drivers/media/platform/sunxi/sun8i-a83t-mipi-csi2/sun8i_a83t_mipi_csi2.c b/drivers/media/platform/sunxi/sun8i-a83t-mipi-csi2/sun8i_a83t_mipi_csi2.c
>> index c82ede3ca0ff..d052ee77ef0a 100644
>> --- a/drivers/media/platform/sunxi/sun8i-a83t-mipi-csi2/sun8i_a83t_mipi_csi2.c
>> +++ b/drivers/media/platform/sunxi/sun8i-a83t-mipi-csi2/sun8i_a83t_mipi_csi2.c
>> @@ -214,14 +214,13 @@ static int sun8i_a83t_mipi_csi2_s_stream(struct v4l2_subdev *subdev, int on)
>> unsigned int lanes_count =
>> csi2_dev->bridge.endpoint.bus.mipi_csi2.num_data_lanes;
>> unsigned long pixel_rate;
>> - /* Initialize to 0 to use both in disable label (ret != 0) and off. */
>> - int ret = 0;
>> + int ret;
>>
>> if (!source_subdev)
>> return -ENODEV;
>>
>> if (!on) {
>> - v4l2_subdev_call(source_subdev, video, s_stream, 0);
>> + ret = v4l2_subdev_call(source_subdev, video, s_stream, 0);
>> goto disable;
>> }
>>
>> @@ -313,6 +312,8 @@ static int sun8i_a83t_mipi_csi2_s_stream(struct v4l2_subdev *subdev, int on)
>> return 0;
>>
>> disable:
>> + if (!on)
>> + ret = 0;
>> phy_power_off(dphy);
>> sun8i_a83t_mipi_csi2_disable(csi2_dev);
>>
>> --
>> 2.35.1
>>
>
