linux-kernel - Re: [PATCH v2 4/5] platform/x86: intel-vbtn: support KEY_ROTATE_LOCK

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Date:   Fri, 10 Nov 2017 01:15:09 +0100
From:   Stefan Brüns <stefan.bruens@...h-aachen.de>
To:     Bastien Nocera <hadess@...ess.net>
CC:     <platform-driver-x86@...r.kernel.org>,
        <linux-input@...r.kernel.org>,
        AceLan Kao <acelan.kao@...onical.com>,
        Andy Shevchenko <andy@...radead.org>,
        Darren Hart <dvhart@...radead.org>,
        <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2 4/5] platform/x86: intel-vbtn: support KEY_ROTATE_LOCK_TOGGLE

On Friday, November 10, 2017 12:30:46 AM CET Bastien Nocera wrote:
> On Thu, 2017-11-09 at 23:44 +0100, Stefan Brüns wrote:
> > The Rotate Lock button event is emitted on the XPS 12 (BIOS A8, but
> > not
> > on BIOS A2).
> > 
> > Signed-off-by: Stefan Brüns <stefan.bruens@...h-aachen.de>
> > ---
> > 
> > Changes in v2:
> > - Emit KEY_ROTATE_LOCK_TOGGLE instead of KEY_ROTATE_DISPLAY
> > - Use separate up/down events
> > 
> >  drivers/platform/x86/intel-vbtn.c | 2 ++
> >  1 file changed, 2 insertions(+)
> > 
> > diff --git a/drivers/platform/x86/intel-vbtn.c
> > b/drivers/platform/x86/intel-vbtn.c index e3f6375af85c..a484bcc6393b
> > 100644
> > --- a/drivers/platform/x86/intel-vbtn.c
> > +++ b/drivers/platform/x86/intel-vbtn.c
> > @@ -42,6 +42,8 @@ static const struct key_entry intel_vbtn_keymap[] = {
> > 
> >  	{ KE_IGNORE, 0xC5, { KEY_VOLUMEUP } },		/* volume-up key release */
> >  	{ KE_KEY, 0xC6, { KEY_VOLUMEDOWN } },		/* volume-down key press */
> >  	{ KE_IGNORE, 0xC7, { KEY_VOLUMEDOWN } },	/* volume-down key release 
*/
> > 
> > +	{ KE_KEY,    0xC8, { KEY_ROTATE_LOCK_TOGGLE } },	/* rotate-lock key
> > press */ +	{ KE_KEY,    0xC9, { KEY_ROTATE_LOCK_TOGGLE } },	/*
> > rotate-lock key release */
> How are those events sent? When pressing and releasing the key, do you
> receive 0xC8 followed by 0xC9? Or do you receive 0xC8 when pressing and
> releasing the first time, and 0xC9 when pressing and releasing a second
> time?
> 
> If the former, then it's not going to work. The release is supposed to
> be ignored, as you send the event with sparse_keymap_report_event().
> 
> If the latter, and there's an actual state, does it disable a device
> on-board, or activate an LED? If so, then it would need to be a switch,
> not a key.

Do you think I don't test the patches before sending? Let me tell you, it 
*does* work.

You could also read the cover letter, where you find more details, putting the 
patches in relation to each other.

Just in case its not yet clear:
The codes are emitted when pressing a button. It is a button, not a switch. 
There is no state handled in hardware. On press (as noted by the code 
comment), event code 0xc8 is emitted. On release, event code 0xc9 is emitted.

Regards,

Stefan
-- 
Stefan Brüns  /  Bergstraße 21  /  52062 Aachen
home: +49 241 53809034     mobile: +49 151 50412019
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