Re: USB gadgets with configfs hang reboot

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Hi,

On 16.01.2016 12:40, Ivaylo Dimitrov wrote:
Hi,

On 16.01.2016 00:48, Tony Lindgren wrote:
Hi all,

Looks like there's some issue with the USB gadgets and configfs.

I'm seeing rmmod of the UDC driver cause a warning and then reboot
hangs the system. This happens at least with v4.4, and I've reproduced
it with dwc3 and musb so it seems to be generic.


Having configfs is not needed, disabling usb gadgets (#
CONFIG_USB_MUSB_GADGET is not set) seems to solved at least poweroff
hang issue on N900. Also, g_nokia is not a module in the config I use,
so I guess the problem is not related whether gadgets are modular or
not. Unfortunately I was not able to test reboot, as rootfs became
corrupted after the first poweroff :( . So it looks like my theory that
onenand corruption on N900 is because poweroff/reboot hangs is wrong.

(copied from "Re: [PATCH] usb: f_mass_storage: test whether thread is running before starting another" thread)

Yet another problem with USB gadget, this time with f_acm - if there is an open /dev/ttyGSn device, it is impossible to reboot/power down the device.

My investigation shown that there is a process(pnatd) that opens /dev/ttyGSn devices, so gserial_free_port() hangs on wait_event(port->close_wait, gs_closed(port)); if I do "cd /sys/bus/platform/drivers/musb-hdrc && echo musb-hdrc.0.auto > unbind".

Unfortunately I don't have serial debug port connector on my N900, so I can't capture logs after the reboot command, however, I suspect it hangs on the same place as with unbind.

That looks weird, as one would expect that close() is called when the kernel kills user processes on reboot/powerdown.

Ivo
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