On Fri, 4 Dec 2009 11:59:25 -0800, Greg KH <greg@xxxxxxxxx> wrote: > On Fri, Dec 04, 2009 at 12:46:57PM -0700, Pete Zaitcev wrote: > > A user found that copying to a USB disk crowds out ISO transfers > > to audio. How is this even possible? > > > > https://bugzilla.redhat.com/show_bug.cgi?id=517438 > > > > > Whilst starting a Torrent with Transmission on a VFAT USB hard drive, audio > > > (through a USB 5.1 sound card) started skipping like nobody's business. > > > > > ALSA sound/usb/usbaudio.c:882: cannot submit datapipe for urb 0, error -28: not enough bandwidth > > > ALSA sound/usb/usbaudio.c:882: cannot submit datapipe for urb 0, error -28: not enough bandwidth > > > > On 2.6.31-rc5-git2. > > That should be normal, bulk is taking up the bandwidth for the bus, so > iso can't be scheduled. > > Or am I missing something? The whole reason for ISO to exist is to receive the guaranteed bandwidth, isn't it (see clause 3.3 of 2.0 spec)? I understand that until the ISO URB is submitted, there's no way for the HCD to know that it should allocate the bandwidth. What is our solution, then? Should we create some sort of "channels" that allocate the bandwidth (what spec calls "prenegotiated")? -- Pete -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
