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

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Message-ID: <1510274387.2624.78.camel@hadess.net>
Date:   Fri, 10 Nov 2017 01:39:47 +0100
From:   Bastien Nocera <hadess@...ess.net>
To:     Stefan Brüns <stefan.bruens@...h-aachen.de>
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 Fri, 2017-11-10 at 01:15 +0100, Stefan Brüns wrote:
> 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.

I guess this was so clear that Darren made the same assumption as me. I
also never said that it wouldn't work, which is why I used "pretty
sure", and asked questions.

> 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.

>From the looks of things, some devices only send the keypresses, and
never the key release, otherwise what would be the point of ignoring
the key release in that table, say for the volume buttons? It's clear
as mud, and there's no comments in the driver to explain that.

If you don't want to answer questions, or are going to be as pissy as
your replies have been, I'm happy to not continue reviewing your
patches. I find patch 2 unreadable, but it might be my tiny tiny little
brain.