Re: [PATCH 1/1 V2] media: usb: uvc: Fix incorrect timeout for Get Request

From: Jim Lin
Date: Thu Jul 13 2017 - 22:12:06 EST

On 2017å07æ11æ 03:47, Laurent Pinchart wrote:
Hi Jim,

Thank you for the patch.

On Monday 10 Jul 2017 14:43:49 Jim Lin wrote:
Section of USB 2.0/3.x specification describes that
"device must be able to return the first data packet to host within
500 ms of receipt of the request. For subsequent data packet, if any,
the device must be able to return them within 500 ms".

This is to fix incorrect timeout and change it from 300 ms to 500 ms
to meet the timing specified by specification for Get Request.

Signed-off-by: Jim Lin <jilin@xxxxxxxxxx>

The patch looks good to me, so

Reviewed-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>

but I'm curious, have you noticed issues with some devices in practice ?

Sometimes this device takes about 360 ms to respond.

usb 1-2: new high-speed USB device number 16
usb 1-2: New USB device found, idVendor=045e, idProduct=0772
usb 1-2: New USB device strings: Mfr=1, Product=2, SerialNumber=0
usb 1-2: Product: Microsoftï LifeCam Studio(TM)
usb 1-2: Manufacturer: Microsoft
uvcvideo: Failed to query (GET_DEF) UVC control 2 on unit 4: -110 (exp. 2).

And it will be working well with correct timeout value.