Re: [PATCH] Add generic driver for Silead tochscreens

[Gregor Riepl <onitake@gmail.com>]

> The firmware has to be calibrated by the vendor for each chip-panel
> combination. If you change the panel even if you keep the same chip it
> is very likely to need some calibration. This might be the reason why
> the finger ID is not working properly.

I see.

So, while your new driver is sufficiently generic, it would still need a
device specific firmware image and there is no way to work around that?

That's kind of a bummer.

Would it be possible to modify the driver in a way that it would work with
different types of panels/chips, even those where finger tracking does not
work correctly?

Also, I see one particular problem concerning existing hardware.
You're retrieving the dimensions, maximum number of trackable fingers and the
name of the firmware image from the DSDT or DTS using device_property_read_*.
The Baytrail tablet I'm testing on does not include such information, and
injecting a modified DSDT is maybe not the best option. Also, the DSDT shipped
I have here does not use GPIO definitions for the control pins, but instead
executes the shutdown/wakeup sequences through _PS3/_PS0 methods. At least
that was my assumption when I looked at it. There are GPIO definitions as
well, but it's not clear what those are used for. Please take a look at the
stanza yourself, if you can:
https://github.com/onitake/gslx680-acpi/blob/master/acpi/gsl-dsdt.aml
I can also send you the complete decompiled DSDT if it helps.