On 07/19/2011 09:43 PM, Vegard Nossum wrote:
> On 19 July 2011 19:53, Arnd Bergmann <arnd@arndb.de> wrote:
>> On Tuesday 19 July 2011 13:33:36 Vegard Nossum wrote:
>>> Any ideas?
>>
>> This is the WARN_ON that Jiri added in 92f6fa09b "TTY: ldisc, do not close
>> until there are readers".
>>
>> Is the login process that triggered this running on the USB device you pass
>> through, or do you have vga or serial console?
> 
> I am using console=ttyS0 console=tty0, so I have both vga and serial
> console. The login process was running on the vga console.

Hi, hmm, originally wait_for_idle was there without checking the retval.
I added it back with checking the retval. I really wonder who is the
other user of the port. Or if there is a bug in refcounting somewhere.

Could you attach output of the kernel run with the patch attached?

thanks,
-- 
js