Re: [PATCH][V2] intel-hid: support 5 array button

["Pali Rohár" <pali.rohar@gmail.com>]

On Wednesday 08 February 2017 08:21:46 Michał Kępień wrote:
> > Hi!
> > 
> > On Saturday 04 February 2017 02:26:05 Darren Hart wrote:
> > > Apologies, this time with Pali's correct email address (aliases fail).
> > > 
> > ...
> > > > 
> > > > Pali, would you care to offer a review or some testing to verify no unexpected
> > > > conflicts with the other dell drivers?
> > 
> > I do not have Dell machine which uses intel-hid.ko so I cannot test this
> > patch. And obviously as it is not loaded it cannot break machines which
> > do not use intel-hid.ko.
> > 
> > > > > +/* 5 button array notification value. */
> > > > > +static const struct key_entry intel_array_keymap[] = {
> > > > > +	{ KE_KEY,    0xC2, { KEY_LEFTMETA} },                /* Press */
> > > > > +	{ KE_IGNORE, 0xC3, { KEY_LEFTMETA} },                /* Release */
> > > > > +	{ KE_KEY,    0xC4, { KEY_VOLUMEUP} },                /* Press */
> > > > > +	{ KE_IGNORE, 0xC5, { KEY_VOLUMEUP} },                /* Release */
> > > > > +	{ KE_KEY,    0xC6, { KEY_VOLUMEDOWN} },              /* Press */
> > > > > +	{ KE_IGNORE, 0xC7, { KEY_VOLUMEDOWN} },	             /* Release */
> > > > > +	{ KE_SW,     0xC8, { .sw = {SW_ROTATE_LOCK, 1} } },   /* Press */
> > > > > +	{ KE_SW,     0xC9, { .sw = {SW_ROTATE_LOCK, 0} } },   /* Release */
> > > > > +	{ KE_KEY,    0xCE, { KEY_POWER} },                   /* Press */
> > > > > +	{ KE_IGNORE, 0xCF, { KEY_POWER} },                   /* Release */
> > > > > +	{ KE_END },
> > > > > +};
> > 
> > This looks suspicious. Why are all release events ignored?
> 
> I also do not have a Dell machine that makes use of this driver, but my
> understanding is that calling sparse_keymap_report_event() with
> autorelease set to true makes release events irrelevant and simplifies
> implementation.  Though each release event still needs a KE_IGNORE entry
> in the keymap so that superfluous KEY_UNKNOWN events are suppressed.

Right, but that means if ACPI/WMI/firmware provides correct information
when key was pressed and when released we should use it. It allow
userspace e.g. measure how long was key pressed or similar thing...

-- 
Pali Rohár
pali.rohar@gmail.com