Hey Mauro,
On Fri, Jul 6, 2012 at 11:41 AM, Ezequiel Garcia <elezegarcia@xxxxxxxxx> wrote:
> On Thu, Jul 5, 2012 at 9:01 PM, Mauro Carvalho Chehab
> <mchehab@xxxxxxxxxx> wrote:
>> Em 05-07-2012 19:36, Sylwester Nawrocki escreveu:
>>> On 07/06/2012 12:11 AM, Mauro Carvalho Chehab wrote:
>>>>> +static int vidioc_dqbuf(struct file *file, void *priv, struct v4l2_buffer *p)
>>>>> +{
>>>>> + struct stk1160 *dev = video_drvdata(file);
>>>>> +
>>>>> + if (!stk1160_is_owner(dev, file))
>>>>> + return -EBUSY;
>>>>> +
>>>>> + return vb2_dqbuf(&dev->vb_vidq, p, file->f_flags& O_NONBLOCK);
>>>>
>>>> Why to use O_NONBLOCK here? it should be doing whatever userspace wants.
>>>
>>> This is OK, since the third argument to vb2_dqbuf() is a boolean indicating
>>> whether this call should be blocking or not. And a "& O_NONBLOCK" masks this
>>> information out from file->f_flags.
>>
>> Ah! OK then.
>>
>> It might be better to initialize it during vb2 initialization, at open,
>> instead of requiring this argument every time vb_dqbuf() is called.
Currently stk1160 doesn't implement an open call, but uses v4l2_fh_open instead.
I'm not sure I should add a separate open, or perhaps you would accept
to initialize this non-block flag in vidioc_reqbufs.
On the other hand, many drivers are doing it at dqbuf, like here at stk1160,
and I was wondering: is it *that* bad?
Thanks,
Ezequiel.
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