On Thursday 21 March 2013, Jason Cooper wrote: > On Thu, Mar 21, 2013 at 06:04:59PM +0100, Soeren Moch wrote: > > > > Now I found out what is going on here: > > > > In itd_urb_transaction() we allocate 9 iTDs for each URB with > > number_of_packets == 64 in my case. The iTDs are added to > > sched->td_list. For a frame-aligned scheduling we need 8 iTDs, the > > 9th one is released back to the front of the streams free_list in > > iso_sched_free(). This iTD was cleared after allocation and has a > > frame number of 0 now. So for each allocation when now_frame == 0 we > > allocate from the dma_pool, not from the free_list. The attached > > patch invalidates the frame number in each iTD before it is sent to > > the scheduler. This fixes the problem without the need to iterate > > over a iTD list. > > > > Signed-off-by: Soeren Moch <smoch@xxxxxx> > > Wow! Great work Soeren! Talk about a long road to a small fix. Thanks > for keeping after it. +1 I hardly understand half of the description above, but that much sounds plausible. Is this a bug fix that should get backported to stable kernels? Arnd -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>