[Acked] [Precise SRU][PULL] fix XPS12 Cypress PS/2 trackpad

[Andy Whitcroft]

On Wed, Apr 03, 2013 at 02:06:31PM -0700, Kamal Mostafa wrote:
> Bug reference:
> 
> 	https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1103594
> 	Cypress Trackpad mis-detected as "PS/2 Cypress Trackpad" on XPS 12
> 
> [IMPACT]
> 
> Due to a firmware change in the Cypress PS/2 trackpad, the driver fails
> to properly detect the trackpad in the Dell XPS12 and possibly other models,
> leaving the trackpad dysfunctional.
> 
> This patch -- a trivial backport from upstream -- fixes the detection glitch
> in the driver.  The patch was cherry-picked into Raring.
> 
> [TESTCASE]
> 
> The patch was deployed as SAUCE in Raring some weeks ago, as well as in the
> Sputnik kernel PPA for Q and P.  It has been verified to fix the problem in
> all three.
> 
> [Regression Potential]
> 
> Low potential for regression: The change will only affect Cypress PS/2
> trackpads (the problem and fix occur only after the trackpad has already been
> detected as a Cypress), and it has been reasonably widely tested on Cypress
> pads with the older firmware via the Sputnik PPA.
> 
> Thanks,
> 
>  -Kamal
> 
> -------- >8 ----------------------------------------------------
> 
> The following changes since commit 985689ad1c3211f4f3a9ce0e2371847320ba873f:
> 
>   UBUNTU: Ubuntu-3.2.0-40.64 (2013-03-25 15:41:43 -0500)
> 
> are available in the git repository at:
> 
>   git://kernel.ubuntu.com/kamal/ubuntu-precise.git cypress-xps12-sru1103594
> 
> for you to fetch changes up to 89623c06dc1531f602dbd4fc497298dfa5ebc583:
> 
>   Input: cypress_ps2 - fix trackpadi found in Dell XPS12 (2013-04-03 13:29:18 -0700)
> 
> ----------------------------------------------------------------
> Kamal Mostafa (1):
>       Input: cypress_ps2 - fix trackpadi found in Dell XPS12
> 
>  drivers/input/mouse/cypress_ps2.c |   19 ++++++++++++++-----
>  1 file changed, 14 insertions(+), 5 deletions(-)

Seems to be specific to one version of one piece of hardware.  Looks
well tested.

I will note that the new code probabally should end:

    return cypress_read_vital_statistics(psmouse);

but that does match the upstream version, so ...

Acked-by: Andy Whitcroft <apw at canonical.com>

-apw