BBB USB error: "Could not flush host TX10 fifo: csr: 2003"

I got this USB error in dmesg repeatedly after more than 8 days of uptime without problems. It happens when any program tries to open the serial port (/dev/ttyACM0):

[762525.340801] ------------[ cut here ]------------
[762525.340815] WARNING: at drivers/usb/musb/musb_host.c:125 musb_h_tx_flush_fifo+0x54/0x80()
[762525.340823] Could not flush host TX10 fifo: csr: 2003
[762525.340828] Modules linked in: cdc_acm
[762525.340849] [] (unwind_backtrace+0x0/0xe0) from [] (warn_slowpath_common+0x4c/0x64)
[762525.340864] [] (warn_slowpath_common+0x4c/0x64) from [] (warn_slowpath_fmt+0x2c/0x3c)
[762525.340878] [] (warn_slowpath_fmt+0x2c/0x3c) from [] (musb_h_tx_flush_fifo+0x54/0x80)
[762525.340893] [] (musb_h_tx_flush_fifo+0x54/0x80) from [] (musb_start_urb+0x1ac/0x6c4)
[762525.340907] [] (musb_start_urb+0x1ac/0x6c4) from [] (musb_cleanup_urb+0x88/0x90)
[762525.340921] [] (musb_cleanup_urb+0x88/0x90) from [] (musb_urb_dequeue+0xf0/0x110)
[762525.340936] [] (musb_urb_dequeue+0xf0/0x110) from [] (unlink1+0xcc/0xdc)
[762525.340950] [] (unlink1+0xcc/0xdc) from [] (usb_hcd_unlink_urb+0x5c/0xb0)
[762525.340964] [] (usb_hcd_unlink_urb+0x5c/0xb0) from [] (usb_kill_urb+0x54/0xf0)
[762525.340983] [] (usb_kill_urb+0x54/0xf0) from [] (acm_port_shutdown+0x70/0xc0 [cdc_acm])
[762525.341005] [] (acm_port_shutdown+0x70/0xc0 [cdc_acm]) from [] (tty_port_shutdown+0x54/0x60)
[762525.341021] [] (tty_port_shutdown+0x54/0x60) from [] (tty_port_close+0x20/0x48)
[762525.341036] [] (tty_port_close+0x20/0x48) from [] (tty_release+0x120/0x430)
[762525.341052] [] (tty_release+0x120/0x430) from [] (__fput+0xec/0x1ec)
[762525.341067] [] (__fput+0xec/0x1ec) from [] (task_work_run+0xb8/0xd0)
[762525.341084] [] (task_work_run+0xb8/0xd0) from [] (do_work_pending+0x80/0x94)
[762525.341100] [] (do_work_pending+0x80/0x94) from [] (work_pending+0xc/0x20)
[762525.341109] —[ end trace 07771a15674e2a45 ]—

I also see this message:

[762525.346020] omap_i2c 44e0b000.i2c: controller timed out
[762525.351664] dummy 0-0034: Error -110 reading from cec:0xfe

There were no responses over the serial line. I’m connecting to an Arduino, which was working fine at first. I’ve tried two of them.

After one reboot, the Arduino didn’t seem to be drawing power. After a second reboot (and thereafter) things seemed to be normal. I switched from a power supply that was supplying too much voltage (6v) to usb power. That may have made a difference but I can’t tell.

Here’s my setup:

BeableBone Black rev A5A
Ubuntu precise (12.04.2 LTS)

kernel ubuntu-armhf 3.8.13-bone20

6V violates the USB specification. It will pop the FET that powers the USB bus. That could make a difference.

You did not say which Arduino, so let’s assume the worse. What did you use as a voltage translator between the BBB and the Arduino?

Gerald