@@ -1394,21 +1394,20 @@ iso_stream_schedule (
/* Behind the scheduling threshold? */
if (unlikely(start < next)) {
+ unsigned now2 = (now - base) & (mod - 1);
/* USB_ISO_ASAP: Round up to the first available slot */
if (urb->transfer_flags & URB_ISO_ASAP)
start += (next - start + period - 1) & -period;
/*
- * Not ASAP: Use the next slot in the stream. If
- * the entire URB falls before the threshold, fail.
+ * Not ASAP: Use the next slot in the stream,
+ * no matter what.
*/
- else if (start + span - period < next) {
- ehci_dbg(ehci, "iso urb late %p (%u+%u < %u)\n",
+ else if (start + span - period < now2) {
+ ehci_dbg(ehci, "iso underrun %p (%u+%u < %u)\n",
urb, start + base,
- span - period, next + base);
- status = -EXDEV;
- goto fail;
+ span - period, now2 + base);
}
}
This is a note to let you know that I have just added a patch titled USB: EHCI: accept very late isochronous URBs to the linux-3.8.y-queue branch of the 3.8.y.z extended stable tree which can be found at: http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.8.y-queue This patch is scheduled to be released in version 3.8.13.8. If you, or anyone else, feels it should not be added to this tree, please reply to this email. For more information about the 3.8.y.z tree, see https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable Thanks. -Kamal ------ From 9ea61fe12e4516a8244577dbbfdbd1249894d6a9 Mon Sep 17 00:00:00 2001 From: Alan Stern <stern@rowland.harvard.edu> Date: Wed, 7 Aug 2013 10:58:05 -0400 Subject: USB: EHCI: accept very late isochronous URBs commit 24f531371de17010f2b1b57d90e42240032e7733 upstream. Since commits 4005ad4390bf (EHCI: implement new semantics for URB_ISO_ASAP) and c75c5ab575af (ALSA: USB: adjust for changed 3.8 USB API) became widely distributed, people have been experiencing problems with audio transfers. The slightest underrun causes complete failure, requiring the audio stream to be restarted. It turns out that the current isochronous API doesn't handle underruns in the best way. The ALSA developers would much rather have transfers that are submitted too late be accepted and complete in the normal fashion, rather than being refused outright. This patch implements the requested approach. When an isochronous URB submission is so late that all its scheduled slots have already expired, a debugging message will be printed in the log and the URB will be accepted as usual. Assuming it was submitted by a completion handler (which is normally the case), it will complete shortly thereafter with all the usb_iso_packet_descriptor status fields marked -EXDEV. This fixes (for ehci-hcd) https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1191603 It should be applied to all kernels that include commit 4005ad4390bf. Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Tested-by: Maksim Boyko <maksboyko@yandex.ru> CC: Clemens Ladisch <clemens@ladisch.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Kamal Mostafa <kamal@canonical.com> --- drivers/usb/host/ehci-sched.c | 13 ++++++------- 1 file changed, 6 insertions(+), 7 deletions(-) -- 1.8.1.2