On (23/03/09 13:55), Ricardo Ribalda wrote:
> Some SunplusIT cameras took a borderline interpretation of the UVC 1.5
> standard, and fill the PTS and SCR fields with invalid data if the
> package does not contain data.
>
> "STC must be captured when the first video data of a video frame is put
> on the USB bus."
>
> Eg:
>
> buffer: 0xa7755c00 len 000012 header:0x8c stc 00000000 sof 0000 pts 00000000
> buffer: 0xa7755c00 len 000012 header:0x8c stc 00000000 sof 0000 pts 00000000
> buffer: 0xa7755c00 len 000668 header:0x8c stc 73779dba sof 070c pts 7376d37a
>
> This borderline/buggy interpretation has been implemented in a variety
> of devices, from directly SunplusIT and from other OEMs that rebrand
> SunplusIT products. So quirking based on VID:PID will be problematic.
>
> All the affected modules have the following extension unit:
> VideoControl Interface Descriptor:
> guidExtensionCode {82066163-7050-ab49-b8cc-b3855e8d221d}
>
> But the vendor plans to use that GUID in the future and fix the bug,
> this means that we should use heuristic to figure out the broken
> packets.
>
> This patch takes care of this.
>
> lsusb of one of the affected cameras:
>
> Bus 001 Device 003: ID 1bcf:2a01 Sunplus Innovation Technology Inc.
> Device Descriptor:
> bLength 18
> bDescriptorType 1
> bcdUSB 2.01
> bDeviceClass 239 Miscellaneous Device
> bDeviceSubClass 2 ?
> bDeviceProtocol 1 Interface Association
> bMaxPacketSize0 64
> idVendor 0x1bcf Sunplus Innovation Technology Inc.
> idProduct 0x2a01
> bcdDevice 0.02
> iManufacturer 1 SunplusIT Inc
> iProduct 2 HanChen Wise Camera
> iSerial 3 01.00.00
> bNumConfigurations 1
>
> Tested-by: HungNien Chen <hn.chen@xxxxxxxxxxxxx>
> Signed-off-by: Ricardo Ribalda <ribalda@xxxxxxxxxxxx>
Reviewed-by: Sergey Senozhatsky <senozhatsky@xxxxxxxxxxxx>
[..]
> +
> + /*
> + * STC (Source Time Clock) is the clock used by the camera. The UVC 1.5
> + * standard states that it "must be captured when the first video data
> + * of a video frame is put on the USB bus".
> + * Most of the vendors, clear the `UVC_STREAM_SCR` bit when the data is
> + * not valid, other vendors always set the `UVC_STREAM_SCR` bit and
> + * expect that the driver only samples the stc if there is data on the
> + * packet.
> + * Ignore all the hardware timestamp information if there is no data
> + * and stc and sof are zero.
> + */
[..]
Thanks!
