On 24.7.2019 22.09, Daniele Palmas wrote:
Hello all, I've a system with kernel 4.14.127 that is showing unexpected xhci-hcd (ASM1042A) errors with a Qualcomm based modem, when running the following test: - signal strength qmi requests looping every few seconds on /dev/cdc-wdm (driver qmi_wwan) - iperf tcp data connection test on the modem network interface The issue is showing also with kernel 5.0 The issues is showing in three different ways: First one: 2019-07-24 15:17:45.495293 kern.err kernel:xhci_hcd 0000:03:00.0: ERROR Transfer event TRB DMA ptr not part of current TD ep_index 28 comp_code 13
2019-07-24 15:17:45.495392 kern.warning kernel:xhci_hcd 0000:03:00.0: Looking for event-dma 000000007725b420 trb-start 000000007725b400 trb-end 000000007725b400 seg-start 000000007725b000 seg-end 000000007725bff0
The xhci driver expects events for transfers in the same order they were queued. For some reason we get an event for the transfer block queued at address b420 before we get events for transfers at b400 and b410. xhci traces of a 5.0 kernel would show in more detail what's going on. can be taken with: mount -t debugfs none /sys/kernel/debug echo 'module xhci_hcd =p' >/sys/kernel/debug/dynamic_debug/control echo 'module usbcore =p' >/sys/kernel/debug/dynamic_debug/control echo 81920 > /sys/kernel/debug/tracing/buffer_size_kb echo 1 > /sys/kernel/debug/tracing/events/xhci-hcd/enable < reproduce the issue > Send output of dmesg Send content of /sys/kernel/debug/tracing/trace Note that the trace file can be huge -Mathias
