Re: [REGRESSION] "bind" a device to a driver doesn't not work anymore

From: Greg KH <gregkh@suse.de>
To: "Éric Piel" <eric.piel@tremplin-utc.net>
Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>,
	Dmitry Torokhov <dtor@insightbb.com>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	linux-input@vger.kernel.org
Subject: Re: [REGRESSION] "bind" a device to a driver doesn't not work anymore
Date: Mon, 12 Oct 2009 07:44:58 -0700	[thread overview]
Message-ID: <20091012144458.GA1326@suse.de> (raw)
In-Reply-To: <4AD31709.4000103@tremplin-utc.net>

On Mon, Oct 12, 2009 at 01:46:17PM +0200, Éric Piel wrote:
> Op 12-10-09 06:35, Dmitry Torokhov schreef:
> > On Saturday 10 October 2009 08:00:29 pm Greg KH wrote:
> >> On Sun, Oct 11, 2009 at 02:04:02AM +0200, ?ric Piel wrote:
> >>> Hello,
> >>>
> >>> After a suspend, I used to do this (to get the PS2 keyboard working
> >>> again), and it used to work fine:
> >>> echo -n "i8042" > /sys/bus/platform/drivers/i8042/unbind ; sleep 1 ; echo
> >>> -n "i8042" > /sys/bus/platform/drivers/i8042/bind
> >>>
> >>> Unfortunately since 2.6.32-rc1, the unbind works fine, but the bind
> >>> returns a "no such device" error now (and the binding is not done). After
> >>> that, additional unbinds also report the error. I think 2.6.31 worked
> >>> fine. Any idea what's going wrong?
> >> Odd.  Any chance you can run 'git bisect' to figure out which patch
> >> might have caused it?
> > 
> > I8042 has been converted to use platform_driver_probe() - we are creating 
> > platform device and platform driver together, there is no chance that some 
> > other device might be driven by i8042 driver.
> I haven't finished bisecting, but indeed, the problem seemed to converge
> toward this patch.
> 
> 
> > Eric, do you still need to fiddle with i8042 to get your keyboard working with 
> > 2.6.32-rc3? We need to make sure that resube works without users needing to 
> > mess with bind/unbind.
> Yes, the keyboard doesn't work after the first resume from ram (the
> later resumes do work). I haven't tried any special option to the i8042
> driver. This is on a HP 2510, in 64 bits.
> 
> Indeed, it would be great to fix this root problem! Is there any bug
> report opened to work on this?
> 
> However, currently the first problem is that unbind works, while bind
> doesn't. Which means anyone doing an unbind will have keyboard and mouse
> lost until the next reboot. That's rather bad because it has been
> recommended for a long time to have this kind of script at resume:
> http://intertrusion.com/files/hp-s2ram.patch
> http://en.opensuse.org/Pm-utils
> 
> So at least, unbind should fail as well as bind.

Ah, I bet I know why bind fails...  Yeah, the i8042_platform_device is
never freed up in the i8042_remove() function in
drivers/input/serio/i8042.c, so when you try to register it again, it
fails.

Dmitry, care to fix this up?  Should be pretty simple.

thanks,

greg k-h