Re: Dell Latitude E7470 touchpad status

["Pali Rohár" <pali.rohar@gmail.com>]

On Tuesday 17 May 2016 22:46:31 Allen_Hung@Dell.com wrote:
> Dell - Internal Use - Confidential 
> 
> On 05/17/2016 09:16 PM, Pali Rohár wrote:
> > On Tuesday 17 May 2016 11:50:06 Ben Gamari wrote:
> >> Pali Rohár <pali.rohar@gmail.com> writes:
> >>
> >>> Hi Ben!
> >>>
> >>> Maybe it could help you, look at my email sent to linux-input ML year
> >>> ago: http://thread.gmane.org/gmane.linux.kernel.input/41210
> >> Hi Pali!
> >>
> >> Thanks, this looks great (assuming this is in fact the protocol spoken
> >> by the E7470 hardware; perhaps Allen could confirm this?). I'll have a
> >> go at rebasing this sometime soon, although it looks like this may take
> >> a fair bit of work as the patch is of the usual... questionable quality
> >> that you'd expect from a hardware vendor and on top of that the driver
> >> itself seems to have evolved significantly.
> > First you need to identify if your touchpad is ALPS or not. If not then
> > work on rebasing is useless.
> >
> > To identify your touchpad there are two ways:
> >
> > 1) Disassemble laptop and look what is under palmrest/keyboard. Latitude
> > laptops used to have good documentation how to do it (on official dell
> > site) and older Exx40 series is not hard to detect it...
> >
> > 2) Look at ALPS detection code. Basically all (known) ALPS touchpad
> > response to some PS/2 sequence with specific answer. So you can compile
> > psmouse.ko/alps.c in debug mode and look if it fit detection or not.
> >
> > I suggest you to do this first investigation step. If touchpad is ALPS
> > or not. I read that some Dell laptops uses synaptics touchpads, so there
> > is non zero chance that touchpad could not be ALPS.
> >
> >>> Also try to look at dell drivers page, there could be linux package for
> >>> your laptop with drivers. Lot of them used to be in dkms format
> >>> (upstream source code with dell changes).
> >>>
> >> I've been unable to find a support package for my machine on the web
> >> site. However, I'm also in touch with Dell through the usual support
> >> channel so perhaps they'll be able to provide a more up-to-date code
> >> drop.
> > IIRC All (new) Latitude laptops can be configured with Ubuntu and in
> > this case they come with preinstalled Ubuntu with that support package.
> >
> > So for sure contact Dell support and ask for it! You can also see Ubuntu
> > as supported system in PDF material about those Latitudes...
> >
> >>> ALPS code from Dell were open source, it was just hard to find it and
> >>> compile it on other then one kernel version. And harder to generate
> >>> patch (like I did in above email)...
> >>>
> >> Right, as I said it looks like rebasing this code drop onto a recent
> >> kernel might require quite some effort.
> > Yes, it would not be simple. Plus for including into mainline kernel
> > needs lot of cleaning (see that email thread).
> >
> >> I do wish that Dell would apply more pressure on their input device
> >> vendors to take upstream support (or open protocol documentation)
> >> seriously. It's very frustrating that we need to go through this same
> >> process with every hardware iteration.
> > If you will be 100% sure that touchpad is ALPS, I could contact ALPS
> > people. They helped me a lot with fixing ALPS touchpad support for my
> > E6440...
> >
> >> Thanks again for the reference, Pali!
> >>
> >> Cheers,
> >>
> >> - Ben
> >>
> 
> I am confirming with Alps team for what protocol version the E7470

Great!

> device is speaking. In fact, they sent me the alps.c which support up
> to V8 and they said it's their latest one.

Currently alps.c in mainline kernel supports protocol versions V1 to V8.
So V9 is missing.

> It seems the driver is older than the patch provided in Pali's link
> (that support up to V9) so I didn't put it here.

That patch which I sent was generated from Ubuntu support package
provided by Dell drivers download package. So somebody in Dell should
know more about it...

> Will get the answer back to you once they confirm with me.
> 
> - Allen

Ok, thanks!

-- 
Pali Rohár
pali.rohar@gmail.com
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