On Thu, 21 Mar 2013, 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. Okay, that is a problem. But it shouldn't be such a big problem, because now_frame should not be equal to 0 very often. > 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. The patch looks okay. However I would like to understand why the 0 frame value messes things up so much. Alan Stern -- 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>