Hi On 21/03/13 20:10, Arnd Bergmann wrote: > 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? > + 1 and I can test on my device. Just one comment: I don't know if -1 is the correct way to init it. Michael > Arnd > -- 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
