On Wednesday 25 May 2016 12:38:15 Allen_Hung@Dell.com wrote:

Dell - Internal Use - Confidential 

On 05/17/2016 11:22 PM, Pali Rohár wrote:

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On Tuesday 17 May 2016 22:46:31 Allen_Hung@Dell.com wrote:

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Dell - Internal Use - Confidential 

On 05/17/2016 09:16 PM, Pali Rohár wrote:

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On Tuesday 17 May 2016 11:50:06 Ben Gamari wrote:

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Pali Rohár [off-list ref] writes:

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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.

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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...

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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).

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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...

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Thanks again for the reference, Pali!

Cheers,

- Ben

I am confirming with Alps team for what protocol version the E7470

Great!

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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.

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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...

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

- Allen

Ok, thanks!

I got responds from Alps and they confirmed that the Alps devices in Dell systems are speaking in protocol V8. The devices that speak in protocol V9 are using different ASIC hardware and they are not used in Dell systems..

- Allen

Hi Allen, thank you for confirmation.

Ben, V8 protocol is supported by linux kernel since version 4.1. Do you
have needed version? If yes and your touchpad does not work, please
compile psmouse.ko in debug mode and send us dmesg output. Maybe there
can be something interesting...

-- 
Pali Rohár
pali.rohar@gmail.com
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