From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pavel Machek Subject: Re: [PATCH v5 2/6] leds: triggers: Add a keyboard backlight trigger Date: Fri, 25 Nov 2016 12:05:58 +0100 Message-ID: <20161125110557.GA13204@amd> References: <05766b18-026a-2af3-def8-9289ddb55234@samsung.com> <201611241751.27696@pali> <5238be1f-d669-07e6-c796-5bc0126cb456@gmail.com> <201611242245.00217@pali> <20161125100140.GC4062@amd> Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="===============7608324091764621321==" Return-path: In-Reply-To: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: ibm-acpi-devel-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org To: Jacek Anaszewski Cc: Matthew Garrett , ibm-acpi-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org, Henrique de Moraes Holschuh , platform-driver-x86-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Hans de Goede , gdg-EWGI23mR1M3QT0dZR+AlfA@public.gmane.org, Richard Purdie , Jacek Anaszewski , Pali =?iso-8859-1?Q?Roh=E1r?= , Darren Hart , linux-leds-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-leds@vger.kernel.org --===============7608324091764621321== Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="5mCyUwZo2JvN/JJP" Content-Disposition: inline --5mCyUwZo2JvN/JJP Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Hi! > >>In view of the above we could report hw brightness changes with POLLPRI > >>on brightness file, but unfortunately we can't because it is impossible > >>to guarantee that readout of brightness file will return the brightness > >>the POLLPRI was meant to notify about. > > > >Agreed here. > > > >>That's why a separate read only file seems to be the only proper > >>solution. > > > >Yes please. And lets make self-changing leds into a trigger, as > >proposed, and as Hans' patch should be already doing. >=20 > We can set one trigger at a time. In this case it will be impossible > to have hw brightness change notifications while other trigger is > active. And that is a _good_ thing. We don't want to deal with "echo heartbeat > kbd_backlight_trigger" and then asking for hardware brightness changes. Lets keep it simple. Yes, monitoring backlight state while hardware updates it is useful. But doing the monitor when some kind of blinking =66rom the kernel is active is just a unneccessary complexity... > >>Moreover, the file should return the brightness from the time > >>of last POLLPRI. > > > >Not sure I agree here. Normally, kernel returns current state for > >variables, does not track "old" state. >=20 > It would report current state. The file called hw_brightness_change > should report last brightness change originating from hardware. > The most recent hw brightness change is still current state from > this perspective. It will be valid until next hw brightness change > occurs. >=20 > Current state does not mean current brightness in this case. Well.. actually... I think this is a little bit over complex and probably unneccessary. I'd let Hans implement whatever he thinks is easiest. Best regards, Pavel --=20 (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blo= g.html --5mCyUwZo2JvN/JJP Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iEYEARECAAYFAlg4GxUACgkQMOfwapXb+vI/BACgisQCx52YD4Yh02eI5rkadrbe pMAAmgK37R1MY26GSAlLopFmS4oLp6Rj =V5XL -----END PGP SIGNATURE----- --5mCyUwZo2JvN/JJP-- --===============7608324091764621321== Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline ------------------------------------------------------------------------------ --===============7608324091764621321== Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline _______________________________________________ ibm-acpi-devel mailing list ibm-acpi-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org https://lists.sourceforge.net/lists/listinfo/ibm-acpi-devel --===============7608324091764621321==--