Hi Oliver, On Monday 12 August 2013 11:01:55 Oliver Neukum wrote: > On Fri, 2013-08-09 at 15:58 +0200, Laurent Pinchart wrote: > > > This is necessary to let the new generation of cameras from LiteOn used > > > in Haswell ULT notebook operate. Otherwise the images will be truncated. > > > > Could you please post the lsusb -v output for the device ? > > It is attached. No it isn't :-) > > Why does it need more buffers, is it a superspeed webcam ? > > No. It is HS. > > > > Signed-off-by: Oliver Neukum <oneukum@xxxxxxx> > > > --- > > > > > > drivers/media/usb/uvc/uvcvideo.h | 4 ++-- > > > 1 file changed, 2 insertions(+), 2 deletions(-) > > > > > > diff --git a/drivers/media/usb/uvc/uvcvideo.h > > > b/drivers/media/usb/uvc/uvcvideo.h index 9e35982..9f1930b 100644 > > > --- a/drivers/media/usb/uvc/uvcvideo.h > > > +++ b/drivers/media/usb/uvc/uvcvideo.h > > > @@ -114,9 +114,9 @@ > > > > > > /* Number of isochronous URBs. */ > > > #define UVC_URBS 5 > > > /* Maximum number of packets per URB. */ > > > > > > -#define UVC_MAX_PACKETS 32 > > > +#define UVC_MAX_PACKETS 128 > > > > That would mean up to 384KiB per URB. While not unreasonable, I'd like to > > know how much data your camera produces to require this. > > How to determine that? The UVC descriptors might provide some information. Do you get errors in the kernel log with UVC_MAX_PACKETS set to 32 ? > > > /* Maximum number of video buffers. */ > > > > > > -#define UVC_MAX_VIDEO_BUFFERS 32 > > > +#define UVC_MAX_VIDEO_BUFFERS 128 > > > > I don't think your camera really needs more than 32 V4L2 (full frame) > > buffers :-) > > Unfortunately, experimental evidence is that it does need them at > resolutions above 640x480 Could you please test it again with UVC_MAX_PACKETS set to 128 and UVC_MAX_VIDEO_BUFFERS set to 32 ? UVC_MAX_VIDEO_BUFFERS sets the maximum number of V4L2 full frame buffers, even 32 is probably way too high. -- Regards, Laurent Pinchart -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
