On 04/07/18 14:16, Mauro Carvalho Chehab wrote:
> Em Fri, 29 Jun 2018 11:40:41 +0200
> Hans Verkuil <[email protected]> escreveu:
>
>> In the vivid driver you want gain to continuous change while autogain
>> is on. However, dev->jiffies_vid_cap doesn't actually change. It probably
>> did in the past, but changes in the code caused this to be a fixed value
>> that is only set when you start streaming.
>>
>> Replace it by jiffies, which is always changing.
>>
>> Signed-off-by: Hans Verkuil <[email protected]>
>> ---
>> diff --git a/drivers/media/platform/vivid/vivid-ctrls.c
>> b/drivers/media/platform/vivid/vivid-ctrls.c
>> index 6b0bfa091592..6eb8ad7fb12c 100644
>> --- a/drivers/media/platform/vivid/vivid-ctrls.c
>> +++ b/drivers/media/platform/vivid/vivid-ctrls.c
>> @@ -295,7 +295,7 @@ static int vivid_user_vid_g_volatile_ctrl(struct
>> v4l2_ctrl *ctrl)
>>
>> switch (ctrl->id) {
>> case V4L2_CID_AUTOGAIN:
>> - dev->gain->val = dev->jiffies_vid_cap & 0xff;
>> + dev->gain->val = (jiffies / HZ) & 0xff;
>
> Manipulating jiffies directly like the above is not a good idea.
Why not? There are HZ jiffies in one second, so this changes the
gain value once a second.
Regards,
Hans
>
> Better to use, instead:
>
> dev->gain->val = (jiffies_to_msecs(jiffies) / 1000) & 0xff;
>
> I'll change the code when applying the patch.
>
>
> Thanks,
> Mauro
>
