Re: Dell Vostro V131 hotkeys revisited

["Pali Rohár" <pali.rohar@gmail.com>]

On Friday 03 July 2015 08:52:44 Michał Kępień wrote:
> > Can you write which WMI call needs to be called?
> 
> Technically, one needs to call method DoBFn (method ID = 1) using GUID
> A80593CE-A997-11DA-B012-B622A1EF5492. Though if you look at the ACPI
> method this GUID maps to (WMBA), you'll notice that the first two
> arguments passed to it (instance number and method ID) are simply
> ignored and the only one that matters is the buffer passed (third
> argument).
> 
> > Last time when I looked into dell-led.c code it called some WMI
> > functions which are just re-implementation of SMI based SMBIOS
> > functions. From information which I have that is just WMI interface for
> > dell SMBIOS one.
> > 
> > I already asked Alex and other people for official ACPI/WMI Dell
> > documentation, so we would be able to solve these hotkey problems once
> > and for all, but I did not get anything yet.
> > 
> > What I found on internet is just this one out-of-dated documentation:
> > http://vpsservice1.sampo.com.tw/sampo_update/document/jimmy/ACPI-WMI%20.pdf
> > 
> > I would suggest you to read it (it is not long) to see Dell WMI methods
> > are just ACPI "wrapper" around Dell SMBIOS (dcdbas.ko driver) used by
> > dell-laptop.ko.
> 
> Great, thanks. I'll look into it.
>  
> > >  2) Pressing hotkey #3 on a Dell Vostro V131 generates WMI event
> > > 0xe025, but no keycode. Apparently, Dell XPS L502X generates the
> > > same WMI event for a hotkey which also generates a keycode [1].
> > > What's the best way to solve this conflict?
> > > 
> > > [1] commit f1566f0: "dell-wmi: Add keys for Dell XPS L502X"
> > 
> > Look at dell-wmi.c source code. Which event format is that? New one
> > (partially described in above PDF document) when dell_new_hk_type is
> > true? Or old one?
> 
> Vostro V131 is using the legacy keymap.
> 
> > Can you please enable pr_debug() in dell-wmi.c and send dmesg output
> > from dell-wmi.ko (specially dell_wmi_notify)?
> 
> Here's what appears in dmesg after pressing hotkey #3:
> 
> ------------------------------------------------------------------------
> dell_wmi: Received WMI event (02 00 00 00 25 e0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00)
> dell_wmi: Key e025 pressed
> wmi: DEBUG Event GUID: 9DBB5994-A997-11DA-B012-B622A1EF5492
> ------------------------------------------------------------------------
> 

It looks like above buffer has format of *new* event (0002 - length of
event, 0000 - type of event, e025 - data). But when using legacy keymap
then dell-wmi.c parse events with old format (which means type=0000 is
dropped and data=e025 is translated to some key).

This is even harder as I thought. Looks like big mess and now I would
say, without documentation for Dell WMI events we are not able to fix
this correctly without breaking other laptops...

========================================================================

CCing kernel Dell developers, can you provide Dell WMI documentation for
events and hotkeys? We have problems with enabling events for additional
buttons/keys on Dell laptops and also parsing WMI events which BIOS/ACPI
generates and send to kernel. Please, I really do not know how to how we
can fix these "hotkey/events" problems.

Something like this document, but updated for new laptops:
http://vpsservice1.sampo.com.tw/sampo_update/document/jimmy/ACPI-WMI%20.pdf

Thanks!

-- 
Pali Rohár
pali.rohar@gmail.com