Re: [PATCH v2] platform/x86: touchscreen_dmi: Add support for setting touchscreen properties from cmdline

["Ilpo Järvinen" <ilpo.jarvinen@linux.intel.com>]

On Fri, 24 May 2024, Hans de Goede wrote:

> Hi All,
> 
> On 5/23/24 4:36 PM, Hans de Goede wrote:
> > On x86/ACPI platforms touchscreens mostly just work without needing any
> > device/model specific configuration. But in some cases (mostly with Silead
> > and Goodix touchscreens) it is still necessary to manually specify various
> > touchscreen-properties on a per model basis.
> > 
> > touchscreen_dmi is a special place for DMI quirks for this, but it can be
> > challenging for users to figure out the right property values, especially
> > for Silead touchscreens where non of these can be read back from
> > the touchscreen-controller.
> > 
> > ATM users can only test touchscreen properties by editing touchscreen_dmi.c
> > and then building a completely new kernel which makes it unnecessary
> > difficult for users to test and submit properties when necessary for their
> > laptop / tablet model.
> > 
> > Add support for specifying properties on the kernel commandline to allow
> > users to easily figure out the right settings. See the added documentation
> > in kernel-parameters.txt for the commandline syntax.
> > 
> > Cc: Gregor Riepl <onitake@gmail.com>
> > Signed-off-by: Hans de Goede <hdegoede@redhat.com>
> > ---
> > Changes in v2:
> > - Refactor ts_data / ts_data_dmi handling a bit (addressing Andy's review)
> > - Accept hex/octal numbers (addressing Andy's review)
> > - Fix ts_parse_props return value (addressing Randy's review)
> > - Use ':' as separator instead of ',', ',' is used in "vendor,option" style
> >   property names, e.g. "silead,home-button"
> > - pr_warn() on invalid syntax since init/main.c does not do this
> > ---
> > Note assuming this gets favourable review(s) in a reasonable timeframe
> > I'm thinking about maybe even adding this to 6.10 as a fix since users
> > not being able to easily test Silead touchscreen settings has been an
> > issue for quite a while now. Without the cmdline option being used this
> > is a no-op so the chance of this causing regressions is close to 0.
> 
> Ok, so here is the other half of this in the form of documentation how
> to use this to figure out the right configuration parameters for Silead
> touchscreens on laptop/tablet models which are not supported yet:
> 
> https://github.com/jwrdegoede/gsl-firmware/blob/master/README.md#determining-the-touchscreens-parameters
> 
> As mentioned above I would like to merge this through the fixes branch
> since this resolves a long standing issue with users not being able to
> use Silead touchscreens on unknown models.
> 
> Ilpo, do you have any objections against me merging this through
> the fixes branch ?

It's fine to take it through fixes I think, especially this early into the 
cycle.

-- 
 i.