Re: Oops in CDC ACM after an Openmoko phone (neo1973) changes its usb interface from ACM to Ethernet

[Oliver Neukum]

Am Sonntag, 2. August 2009 18:40:56 schrieb Alex Riesen:
> [   75.453444] Call Trace:
> [   75.453444]  [<ffffffff812a77b2>] usb_autopm_get_interface+0xe/0x10
> [   75.453444]  [<ffffffffa0072e19>] acm_port_down+0x3f/0x1bb [cdc_acm]
> [   75.453444]  [<ffffffff811f0af1>] ? tty_port_close_start+0xc1/0x153
> [   75.453444]  [<ffffffffa0073258>] acm_tty_close+0x3d/0x83 [cdc_acm]
> [   75.453444]  [<ffffffff811eaca7>] tty_release_dev+0x1bf/0x4e8
> [   75.453444]  [<ffffffffa00732c3>] ? acm_tty_open+0x25/0x2ae [cdc_acm]

This can happen only if acm_port_down() fails to detect that the device has
been disconnected, as it calls usb_autopm_get_interface()
only if acm->dev != NULL.
This however should not happen if acm_disconnect runs.

Can you put a printk into acm_disconnect and recompile with CONFIG_USB_DEBUG?

	Regards
		Oliver

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