[stable] [PATCH] Input: ALPS - add interleaved protocol support (Dell E6x00 series)

Dmitry Torokhov dmitry.torokhov at gmail.com
Thu Jan 21 17:30:48 UTC 2010


On Thu, Jan 21, 2010 at 08:23:28AM -0800, Greg KH wrote:
> On Wed, Jan 20, 2010 at 11:54:38PM -0800, Dmitry Torokhov wrote:
> > 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 <sebastian_kapfer at gmx.net>
> > > > 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 <sebastian_kapfer at gmx.net>
> > > > Signed-off-by: Dmitry Torokhov <dtor at mail.ru>
> > > > ---
> > > > 
> > > > Cherrypick to 2.6.31 by Andy Isaacson <adi at hexapodia.org>.  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.
> 
> So is this something that you, as the maintainer of the subsystem, would
> recommend that I consider for the -stable tree because of this
> situation?
> 

Yes, I am recommending it. The new behavior should be mostly contained
by ALPS_INTERLEAVED flag that is only set for one particular signature;
the rest of devices should not be affected.

The patch could be made smaller (there are some comments and a bit of
restructuring that could be cut out) but given that it is in Debian for
some time I question whether introducing 3rd, less tested variant to
reduce patch line count makes sense.

Thanks.

-- 
Dmitry




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