Re: [Patch v5 1/2] media: v4l: ti-vpe: Add CAL v4l2 camera capture driver

Hans Verkuil
2015-12-14T14:42:00Z

On 12/11/2015 11:16 PM, Benoit Parrot wrote:
> Mauro Carvalho Chehab <mchehab@osg.samsung.com> wrote on Thu [2015-Dec-03 11:19:22 -0200]:
>>> +static int cal_enum_framesizes(struct file *file, void *fh,
>>> + struct v4l2_frmsizeenum *fsize)
>>> +{
>>> + struct cal_ctx *ctx = video_drvdata(file);
>>> + const struct cal_fmt *fmt;
>>> + struct v4l2_subdev_frame_size_enum fse;
>>> + int ret;
>>> +
>>> + ctx_dbg(2, ctx, "%s\n", __func__);
>>
>> This s a general note: do you really need tracing-like debug macros
>> all around the code?
>>
>> You could easily check if the functions are called via trace.
>
> True but that also mean to rebuild the kernel in order to
> get to it since function tracing is usually not enabled
> by default.
>

You can enable debugging by doing:

echo 2 >/sys/class/video4linux/video0/dev_debug

See also: Documentation/video4linux/v4l2-framework.txt, section "video device
debugging" for more info.

That's always available and basically does what you want.

Regards,

Hans