Hi Andy, And we meet again. :)
On Wed, Jun 06, 2018 at 06:36:35PM +0300, Andy Shevchenko wrote: > On Wed, 2018-06-06 at 17:12 +0300, Mathias Nyman wrote: > > On 04.06.2018 18:28, Sudip Mukherjee wrote: > > > On Thu, May 24, 2018 at 04:35:34PM +0300, Mathias Nyman wrote: > > > > > > > Odd and unlikely, but to me this looks like some issue in allocating > > dma memory > > from pool using dma_pool_zalloc() > > > > Adding people with DMA knowledge to cc, maybe someone knows what is > > going on. > > > > Here's the story: > > Sudip sees usb issues on a Intel Atom based board with 4.14.2 kernel. > > All tracing points to dma_pool_zalloc() returning the same dma address > > block on > > consecutive calls. > > > > In the failing case dma_pool_zalloc() is called 3 - 6us apart. > > > > <...>-26362 [002] .... 1186.756739: xhci_ring_mem_detail: MATTU > > xhci_segment_alloc dma @ 0x000000002d92b000 > > <...>-26362 [002] .... 1186.756745: xhci_ring_mem_detail: MATTU > > xhci_segment_alloc dma @ 0x000000002d92b000 > > <...>-26362 [002] .... 1186.756748: xhci_ring_mem_detail: MATTU > > xhci_segment_alloc dma @ 0x000000002d92b000 > > > > dma_pool_zalloc() is called from xhci_segment_alloc() in > > drivers/usb/host/xhci-mem.c > > see: > > https://elixir.bootlin.com/linux/v4.14.2/source/drivers/usb/host/xhci- > > mem.c#L52 > > > > prints above are custom traces added right after dma_pool_zalloc() > > For better understanding it would be good to have dma_pool_free() calls > debugged as well. So, I am adding another trace event for dma_pool_free() and continuing with the test. Is there anything else that I should be adding as debug? -- Regards Sudip _______________________________________________ iommu mailing list [email protected] https://lists.linuxfoundation.org/mailman/listinfo/iommu
