Hi,
I start my buildroot-linux on a custom board and it can be that it starts four, five or six times well that means all usb devices are there:
lsusb
Bus 004 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 003 Device 012: ID 1546:01a8 U-Blox AG [u-blox 8]
Bus 003 Device 005: ID 0424:2422 Standard Microsystems Corp.
Bus 003 Device 009: ID 1fc9:0103 NXP Semiconductors
Bus 003 Device 007: ID 1546:1143 U-Blox AG
Bus 003 Device 002: ID 0424:2517 Standard Microsystems Corp. Hub
Bus 003 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 002 Device 002: ID 0424:5744 Standard Microsystems Corp.
Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 001 Device 002: ID 0424:2744 Standard Microsystems Corp.
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Another time some of the devices are absent:
lsusb
Bus 004 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 003 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 002 Device 002: ID 0424:5744 Standard Microsystems Corp.
Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 001 Device 002: ID 0424:2744 Standard Microsystems Corp.
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
In this case during the start procedure an error occurs:
[ 85.043982] xhci-hcd xhci-hcd.1.auto: ERROR mismatched command completion event, cmd_dma: 4249149424, cmd_dequeue_dma: 4249145344
The error comes from the file "xhci-ring.c" in a kernel modul. I printed the both adresses to see why the error occurs, if they are equal there is no error.
How can it be that the error only occurs at nearly every fourth or fiifth start? What reasons are for the difference of the addresses? It looks to me like a ring buffer and some entries are displaced but why?
Regards,
Ralph
[ 85.043982] xhci-hcd xhci-hcd.1.auto: ERROR mismatched command completion event, cmd_dma: 4249149424, cmd_dequeue_dma: 4249145344