Hi Sarah, On Friday 17 June 2011 20:19:01 Sarah Sharp wrote: > On Fri, Jun 17, 2011 at 07:01:10PM +0200, Laurent Pinchart wrote: > > On Friday 17 June 2011 18:46:20 Sarah Sharp wrote: > > > On Fri, Jun 17, 2011 at 10:18:39AM +0200, Laurent Pinchart wrote: > > > > On Thursday 16 June 2011 22:20:22 Alan Stern wrote: > > > > > On Thu, 16 Jun 2011, Sarah Sharp wrote: > > > > > > On Thu, Jun 16, 2011 at 03:39:11PM -0400, Alan Stern wrote: > > > > > > > That's appropriate. But nobody should ever set an isochronous > > > > > > > URB's status field to -EPROTO, no matter whether the device is > > > > > > > connected or not and no matter whether the host controller is > > > > > > > alive or not. > > > > > > > > > > > > But the individual frame status be set to -EPROTO, correct? > > > > > > That's what Alex was told to do when an isochronous TD had a > > > > > > completion code of "Incompatible Device Error". > > > > > > > > > > Right. -EPROTO is a perfectly reasonable code for a frame's > > > > > status. But not for an isochronous URB's status. There's no > > > > > reason for uvcvideo to test for it. > > > > > > > > The uvcvideo driver tests for -EPROTO for interrupt URBs only. For > > > > isochronous URBs it tests for -ENOENT, -ECONNRESET and -ESHUTDOWN. > > > > > > So is uvc_status_complete() shared between interrupt and isochronous > > > URBs then? > > > > No, uvc_status_complete() handles status URBs (interrupt only), and > > uvc_video_complete() handles video URBs (isochronous or bulk, depending > > on the device). > > Huh, that's very odd then. I could have sworn I was getting missed > service interval events (which are only for isochronous transfers) and > then seeing the "Non-zero" message. And the userspace video definitely > froze before my patch and did not freeze after the patch was applied. > I'll have to look more closely at the logs. The log excerpt message you posted was Jun 15 17:37:11 talon kernel: [ 117.987769] uvcvideo: Non-zero status (-18) in video completion handler. That's printed by uvc_video_complete(). uvc_status_complete() would have printed "Non-zero status (-18) in status completion handler". There's nothing wrong with your analysis of the problem, you just picked the wrong uvcvideo function. -- 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
