Re: [PATCH] media: uvcvideo: Pick first best alternate setting insteed of last

[Karel Janda <karel1@tutanota.com>]

Hi Laurent,

   I think again and I have more good news:
I installed patch for uvc_video.c  on running kernel from
 https://kernel.ubuntu.com/mainline/v6.6-rc5/

Patch works as expected, with working video on Newmine camera  at my
Linux karel1-HP-630 6.6.0-060600rc5-generic #202310081731 SMP PREEMPT_DYNAMIC 
Sun Oct  8 21:38:25 UTC 2023 x86_64 x86_64 x86_64 GNU/Linux

insmod uvcvideo trace=0x400 #logs into kernel.log:
[ 1223.890865] usb 2-1.1: Found UVC 1.00 device Newmine Camera (0402:8841)
[ 1223.917166] usbcore: registered new interface driver uvcvideo
[ 1339.107555] usb 2-1.1: Device requested 320 B/frame bandwidth
[ 1339.107566] usb 2-1.1: Selecting alternate setting 1 (1024 B/frame bandwidth)
[ 1339.115788] usb 2-1.1: Allocated 5 URB buffers of 32x1024 bytes each
So we all can be sure, that patch is OK also for 6.6 Linux kernel.

sincerely

Karel Janda


20. 10. 2023 16:09 od karel1@tutanota.com:

> Hi Laurent,
>
>  you pleased me very much, also for your quick reply.
>
> 1)
>   The patch is exactly the same as final state of my debugging.
> I just succesfully probe it against > uvc_video.c <https://elixir.bootlin.com/linux/v6.6-rc6/source/drivers/media/usb/uvc/uvc_video.c>>  source on my PC running
> Linux HP-Pro-A-MT 6.5.0-9-generic #9-Ubuntu SMP PREEMPT_DYNAMIC
> Sat Oct  7 01:35:40 UTC 2023 x86_64 x86_64 x86_64 GNU/Linux
> with Newmine camera.
> /The patch also doesn't hurt my other UVC 1.0 camera, Genius Qcam 6000./
> All my 6.5.0 uvc*.c  files in uvc directory are clean of any other changes I used for tests before,
> only the path of one single line in one file is there now.
>
>   Now I also carefully compare 6.5.0 > uvc_video.c <https://elixir.bootlin.com/linux/v6.6-rc6/source/drivers/media/usb/uvc/uvc_video.c>>  original  (before the patch) with currect Linux sources at
> https://elixir.bootlin.com/linux/v6.6-rc6/source/drivers/media/usb/uvc/uvc_video.c
> and also at
> https://github.com/torvalds/linux/blob/master/drivers/media/usb/uvc/uvc_video.c
>    These are different only in few blank characters :)).
>
>   I am not able to run last git 6.6 kernel just now, but I hope that my verification by 6.5.0 will be enough.
> If is necessery - let me now, I will try compile last kernel on different, dedicated computer.
> (I never work with such a big git project. I sometimes used other's ppa results.)
>
> 2)
>   You can mention my name in linux git history, I will be glad.
>
> best regards
>
> Karel Janda
>
>
> 20. 10. 2023 0:24 od laurent.pinchart@ideasonboard.com:
>
>> ---
>> Karel, could you please test this patch ? Please also let me know if you
>> are fine having your name recorded in the kernel git history with the
>> Reported-by and Suggested-by tags above. If not, I will drop them.
>> ---
>> drivers/media/usb/uvc/uvc_video.c | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/media/usb/uvc/uvc_video.c b/drivers/media/usb/uvc/uvc_video.c
>> index 28dde08ec6c5..7cbf4692bd87 100644
>> --- a/drivers/media/usb/uvc/uvc_video.c
>> +++ b/drivers/media/usb/uvc/uvc_video.c
>> @@ -1954,7 +1954,7 @@ static int uvc_video_start_transfer(struct uvc_streaming *stream,
>>
>> /* Check if the bandwidth is high enough. */
>> psize = uvc_endpoint_max_bpi(stream->dev->udev, ep);
>> -			if (psize >= bandwidth && psize <= best_psize) {
>> +			if (psize >= bandwidth && psize < best_psize) {
>> altsetting = alts->desc.bAlternateSetting;
>> best_psize = psize;
>> best_ep = ep;
>> --
>>
>
>