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

[Alex Riesen]

On Sun, Aug 2, 2009 at 19:19, Oliver Neukum<oliver@xxxxxxxxxx> wrote:
> Am Sonntag, 2. August 2009 18:40:56 schrieb Alex Riesen:
>> [ Â 75.453444] Call Trace:
>> [ Â 75.453444] Â[<ffffffff812a77b2>] usb_autopm_get_interface+0xe/0x10
>> [ Â 75.453444] Â[<ffffffffa0072e19>] acm_port_down+0x3f/0x1bb [cdc_acm]
>> [ Â 75.453444] Â[<ffffffff811f0af1>] ? tty_port_close_start+0xc1/0x153
>> [ Â 75.453444] Â[<ffffffffa0073258>] acm_tty_close+0x3d/0x83 [cdc_acm]
>> [ Â 75.453444] Â[<ffffffff811eaca7>] tty_release_dev+0x1bf/0x4e8
>> [ Â 75.453444] Â[<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?

I put the printks at some random lines in acm_disconnect (as of v2.6.31-rc2)
and turned CONFIG_USB_DEBUG on. It is definitely not the same kernel
I tried before (and sadly, it does not go oops), but it still has
tty_port_close_start: count = -1
Dmesg attached

I'm retrying with recent kernels (hopefully I'll get enough data left
on the screen),
I shall try to find the -rc2 which oopses (I suspect it is the one
just before -rc3).

Attachment: usbdeb
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