Comment 175 for bug 296610

On Wed, Jan 20, 2010 at 08:13:03PM -0800, Greg KH wrote:
> On Fri, Jan 15, 2010 at 10:11:22AM -0800, Andy Isaacson wrote:
> > From: Sebastian Kapfer <email address hidden>
> > Date: Tue, 15 Dec 2009 08:39:50 -0800
> > Subject: [PATCH] Input: ALPS - add interleaved protocol support (Dell E6x00 series)
> >
> > commit 1d9f26262aef6d63ff65eba0fd5f1583f342b69b upstream
> >
> > Properly handle version of the protocol where standard PS/2 packets
> > from trackpoint are stuffed into middle (byte 3-6) of the standard
> > ALPS packets when both the touchpad and trackpoint are used together.
> >
> > The patch is based on work done by Matthew Chapman and additional
> > research done by David Kubicek and Erik Osterholm:
> >
> > https://bugs.launchpad.net/ubuntu/+source/linux/+bug/296610
> >
> > Many thanks to David Kubicek for his efforts in researching fine points
> > of this new version of the protocol, especially interaction between pad
> > and stick in these models.
> >
> > Signed-off-by: Sebastian Kapfer <email address hidden>
> > Signed-off-by: Dmitry Torokhov <email address hidden>
> > ---
> >
> > Cherrypick to 2.6.31 by Andy Isaacson <email address hidden>. Tested on
> > Dell E4300.
>
> What -stable tree is this for? .31 is no longer being maintained. Is
> this the proper patch for .32? .27?
>
> >
> > drivers/input/mouse/alps.c | 252 +++++++++++++++++++++++++++++++++++++++-----
> > drivers/input/mouse/alps.h | 1 +
> > 2 files changed, 228 insertions(+), 25 deletions(-)
>
> Ick, that's a big patch, and kind of violates the -stable rules, right?
> It's a "add new functionality" type thing that you are doing here from
> what I can tell. This doesn't fix a regression, does it?
>

Well, yes and no. As shipped .32 (and earlier) has the signature for
ALPS that is installed in those newer Latitudes so we try to activate
ALPS protocol for their touchpads. Unfortunately without the patch the
protocol desyncs all the time, making trackpoint/touchpad unuseable.

IOW if you are an owner of said Latitude you want this patch _very
much_. But yes, the patch is sizeable.

--
Dmitry