linux-kernel - Re: [PATCH 2/2] dell-wmi-base: Handle Win-key Lock/Unlock events

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Message-ID: <20241030204022.apkxwkpwki3pk5yj@pali>
Date: Wed, 30 Oct 2024 21:40:22 +0100
From: Pali Rohár <pali@...nel.org>
To: Kurt Borja <kuurtb@...il.com>
Cc: Dell.Client.Kernel@...l.com, hdegoede@...hat.com,
	ilpo.jarvinen@...ux.intel.com, linux-kernel@...r.kernel.org,
	platform-driver-x86@...r.kernel.org, w_armin@....de
Subject: Re: [PATCH 2/2] dell-wmi-base: Handle Win-key Lock/Unlock events

On Wednesday 30 October 2024 17:37:38 Kurt Borja wrote:
> On Wed, Oct 30, 2024 at 09:20:29PM +0100, Pali Rohár wrote:
> > On Wednesday 30 October 2024 17:11:40 Kurt Borja wrote:
> > > On Wed, Oct 30, 2024 at 07:34:36PM +0100, Pali Rohár wrote:
> > > > On Wednesday 30 October 2024 15:15:33 Kurt Borja wrote:
> > > > > Some Alienware devices have a key that locks/unlocks the Win-key. This
> > > > 
> > > > Please specify (in comment / commit message) which devices. It would
> > > > help other developers in future to track for which device is this event
> > > > needed.
> > > 
> > > I will!
> > > 
> > > > 
> > > > > key triggers a WMI event that should be ignored, as it's handled
> > > > > internally by the firmware.
> > > > 
> > > > Can be this handling in FW ignored? So OS can use this key for any other
> > > > functionality?
> > > 
> > > Probably not. FW locks the Win-key regardless of how the event is
> > > handled.
> > > 
> > > > 
> > > > Anyway, what is that Win-key and its lock?
> > > 
> > > Win-key is the LEFTMETA key and the lock key is the RIGHTMETA key.
> > 
> > Ok, thanks for info.
> > 
> > So if the firmware handles and process RIGHTMETA key, it means that the
> > RIGHTMETA key is not usable for generic purposes on this machine?
> 
> Yes, it is not. Unless, of course we find a way to change FW default
> behavior.

That is sad... and also (negatively) surprising for me that another
generic-purpose key is behaving in this way. Mentioning this in commit
message would be useful as this is really something unexpected.

> > 
> > > > 
> > > > > Signed-off-by: Kurt Borja <kuurtb@...il.com>
> > > > > ---
> > > > >  drivers/platform/x86/dell/dell-wmi-base.c | 6 ++++++
> > > > >  1 file changed, 6 insertions(+)
> > > > > 
> > > > > diff --git a/drivers/platform/x86/dell/dell-wmi-base.c b/drivers/platform/x86/dell/dell-wmi-base.c
> > > > > index 502783a7a..37fc0371a 100644
> > > > > --- a/drivers/platform/x86/dell/dell-wmi-base.c
> > > > > +++ b/drivers/platform/x86/dell/dell-wmi-base.c
> > > > > @@ -80,6 +80,12 @@ static const struct dmi_system_id dell_wmi_smbios_list[] __initconst = {
> > > > >  static const struct key_entry dell_wmi_keymap_type_0000[] = {
> > > > >  	{ KE_IGNORE, 0x003a, { KEY_CAPSLOCK } },
> > > > >  
> > > > > +	/* Win-key Lock */
> > > > > +	{ KE_IGNORE, 0xe000, {KEY_RESERVED} },
> > > > 
> > > > nit: code style: spaces around KEY_RESERVED.
> > > 
> > > I will fix it.
> > > 
> > > > 
> > > > Is not there some better constant for this KEY_*?
> > > 
> > > We could assign it KEY_RIGHTMETA.
> > 
> > Just to note that if the key is marked with KE_IGNORE, its value is not
> > used. But for documentation purposes it is a good idea to have written
> > there something other than KEY_RESERVED -- if it is possible.
> > 
> > For example it can be useful if somebody in future figure out how to
> > turn off processing of this key in firmware...
> 
> Thanks I will replace it with KEY_RIGHTMETA.
> 
> Kurt
> 
> > 
> > > > 
> > > > > +
> > > > > +	/* Win-key Unlock */
> > > > > +	{ KE_IGNORE, 0xe001, {KEY_RESERVED} },
> > > > > +
> > > > >  	/* Key code is followed by brightness level */
> > > > >  	{ KE_KEY,    0xe005, { KEY_BRIGHTNESSDOWN } },
> > > > >  	{ KE_KEY,    0xe006, { KEY_BRIGHTNESSUP } },
> > > > > -- 
> > > > > 2.47.0
> > > > >