Re: [PATCH 1/3] usb,console: Fix regression in usb console on kernel boot

[Alan Cox <alan@lxorguk.ukuu.org.uk>]

On Wed, 17 Jun 2009 21:20:07 -0500
Jason Wessel <jason.wessel@windriver.com> wrote:

> The commit 335f8514f200e63d689113d29cb7253a5c282967 introduced a
> regression which stopped usb consoles from working correctly as a
> kernel boot console as well as interactive login device.
> 
> The addition of the serial_close() which in turn calls
> tty_port_close_start() will change the reference count of port.count
> and warn about it.  The usb console code had previously incremented
> the port.count to indicate it was making use of the device as a
> console and the forced change causes a double open on the usb device
> which leads to a non obvious kernel oops later on when the tty is
> freed.
> 
> To fix the problem instead make use of port->console to track if the
> port is in fact an active console port to avoid double initialization
> of the usb serial device.  The port.count is incremented and
> decremented only with in the scope of usb_console_setup() for the
> purpose of the low level driver initialization.

Acked-by: Alan Cox <alan@linux.intel.com>