Re: Elantech touchpad does not work on Asus

[Dmitry Torokhov <dmitry.torokhov@gmail.com>]

Hi Ulrik,

On Thu, Mar 19, 2015 at 11:05:46PM +0100, ulrik.debie-os@e2big.org wrote:
> Hi all,
> 
> I looked at the bugzilla bugreport on 
> https://bugzilla.kernel.org/show_bug.cgi?id=84491
> "Elantech touchpad does not work on Asus TransformerBook Flip 500"
> 
> There are problems reported on two variants:
> Asus TransformerBook Flip TP500LN
> Asus TP500LN
> 
> George (in CC:) helped me to investigate on his hardware what happened
> by trying a few patches and reporting what happens.
> 
> It seems that the absolute mode setting somehow gets cancelled after the
> elantech drivers initializes. This results in relative motion packets
> coming in, elantech driver not recognizing them and consequentially
> "lost sync at byte 6" messages.
> 
> When one, after the psmouse driver is loaded, does the following:
> echo 1 > /sys/devices/platform/i8042/serio4/reg_07
> ,the touchpad will work like a charm until suspend2ram. After a 
> suspend2ram, another echo is required. 
> 
> This exact same value is written during initialization of v4 hardware. 
> As a test, I even read it back in elantech_set_absolute_mode after 
> writing and at that moment in the driver the value 1 is read.
> 
> But when one performs the read later on the commandline of reg_07, value
> 0 is read, so probably for a reason unknown to me, the value goes to
> 0 because of some timeout or serio communiation.
> 
> I also tried putting elantech_set_input_params call in front of
> elantech_set_absolute_mode, but that didn't help either.
> 
> Also the suspend2ram seems to result in the same thing.
> 
> Anyone an idea why this reg_07 1 value could become a 0 between the time
> the function elantech_set_absolute_mode during loading of the psmouse
> module and the time when reading the value from sysfs from the 
> command line ?

Hmm, so after Elantech code has done with the init you see the correct
value in r7? Psmouse driver does [re]set scale, rate and resolution
after protocol has been initialized, maybe that confuses Elantech in the
same fashion as it does Focaltech?

Thanks.

-- 
Dmitry