From: Pavel Machek <pavel@ucw.cz> To: Hans de Goede <hdegoede@redhat.com> Cc: Jacek Anaszewski <jacek.anaszewski@gmail.com>, Tony Lindgren <tony@atomide.com>, Jacek Anaszewski <j.anaszewski@samsung.com>, linux-leds@vger.kernel.org, linux-omap@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Darren Hart <dvhart@infradead.org> Subject: Re: Three different LED brightnesses (was Re: PM regression with LED changes in next-20161109) Date: Sun, 13 Nov 2016 21:45:25 +0100 [thread overview] Message-ID: <20161113204525.GA15072@amd> (raw) In-Reply-To: <3a3bb3f8-e54a-e7d0-da30-7f90b00c29b3@redhat.com> [-- Attachment #1: Type: text/plain, Size: 2171 bytes --] Hi! > >No, that's just adding more mess on the system. > > > >Here's better proposal: > > > >brightness (write): what we do today. (Mess, but too late to change it) > > (read): -Esomething or what we do today (if someone > > acutally uses it) > > As said Jacek has already nacked any changes to read behavior. > > > (poll): -Esomething > > Making poll() on sysfs attributes return -Esomething is not possible, > the internal sysfs API does not allow this. > > >current_brightness (write): -Esomething, or maybe change brightness > > for triggers that can work with that > > (read, poll): if the current trigger can get current > > state of led, do it, otherwise -Esomething... > > or maybe file should be simply hidden from sysfs. > > So write is -EINVAL and read is the same as what brightness currently does, > so I see no use in introducing this new file. No, read is not same as current brightness file. Currently, reading brightness file returns either current brightness or maximum brightness, and userspace can't tell which is which. > >trigger_max_brightness (read,write): change the maximum brightness for > > a trigger. > > (poll): -Esomething > > The write behavior here is the same as what brightness currently does > and the read behavior is that of what I suggested for No, it is not. "brightness" behaviour is currently broken, as it sets either current brightness or maximum trigger brightness. > We've 2 sorts of brightness really: > > 1) transient brightness, aka current brightness, when blinking or > triggers are used this will switch many times a second > between off and some on level. > > 2) non-transient brightness, for non blinking leds this is the > actual brightness, for blinking leds this is the brightness > level used when the led is on. Yes, and we want reasonable interface where userspace sees those two brightnesses. Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html [-- Attachment #2: Digital signature --] [-- Type: application/pgp-signature, Size: 181 bytes --]
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From: pavel@ucw.cz (Pavel Machek) To: linux-arm-kernel@lists.infradead.org Subject: Three different LED brightnesses (was Re: PM regression with LED changes in next-20161109) Date: Sun, 13 Nov 2016 21:45:25 +0100 [thread overview] Message-ID: <20161113204525.GA15072@amd> (raw) In-Reply-To: <3a3bb3f8-e54a-e7d0-da30-7f90b00c29b3@redhat.com> Hi! > >No, that's just adding more mess on the system. > > > >Here's better proposal: > > > >brightness (write): what we do today. (Mess, but too late to change it) > > (read): -Esomething or what we do today (if someone > > acutally uses it) > > As said Jacek has already nacked any changes to read behavior. > > > (poll): -Esomething > > Making poll() on sysfs attributes return -Esomething is not possible, > the internal sysfs API does not allow this. > > >current_brightness (write): -Esomething, or maybe change brightness > > for triggers that can work with that > > (read, poll): if the current trigger can get current > > state of led, do it, otherwise -Esomething... > > or maybe file should be simply hidden from sysfs. > > So write is -EINVAL and read is the same as what brightness currently does, > so I see no use in introducing this new file. No, read is not same as current brightness file. Currently, reading brightness file returns either current brightness or maximum brightness, and userspace can't tell which is which. > >trigger_max_brightness (read,write): change the maximum brightness for > > a trigger. > > (poll): -Esomething > > The write behavior here is the same as what brightness currently does > and the read behavior is that of what I suggested for No, it is not. "brightness" behaviour is currently broken, as it sets either current brightness or maximum trigger brightness. > We've 2 sorts of brightness really: > > 1) transient brightness, aka current brightness, when blinking or > triggers are used this will switch many times a second > between off and some on level. > > 2) non-transient brightness, for non blinking leds this is the > actual brightness, for blinking leds this is the brightness > level used when the led is on. Yes, and we want reasonable interface where userspace sees those two brightnesses. Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html -------------- next part -------------- A non-text attachment was scrubbed... Name: signature.asc Type: application/pgp-signature Size: 181 bytes Desc: Digital signature URL: <http://lists.infradead.org/pipermail/linux-arm-kernel/attachments/20161113/f90abee5/attachment.sig>
next prev parent reply other threads:[~2016-11-13 20:45 UTC|newest] Thread overview: 102+ messages / expand[flat|nested] mbox.gz Atom feed top 2016-11-09 19:23 PM regression with LED changes in next-20161109 Tony Lindgren 2016-11-09 19:23 ` Tony Lindgren 2016-11-09 20:45 ` Jacek Anaszewski 2016-11-09 20:45 ` Jacek Anaszewski 2016-11-10 8:49 ` Hans de Goede 2016-11-10 8:49 ` Hans de Goede 2016-11-10 12:56 ` Jacek Anaszewski 2016-11-10 12:56 ` Jacek Anaszewski 2016-11-10 13:04 ` Hans de Goede 2016-11-10 13:04 ` Hans de Goede 2016-11-10 13:55 ` Jacek Anaszewski 2016-11-10 13:55 ` Jacek Anaszewski 2016-11-10 16:36 ` Pavel Machek 2016-11-10 16:36 ` Pavel Machek 2016-11-10 16:29 ` Pavel Machek 2016-11-10 16:29 ` Pavel Machek 2016-11-10 16:44 ` Hans de Goede 2016-11-10 16:44 ` Hans de Goede 2016-11-10 20:48 ` Pavel Machek 2016-11-10 20:48 ` Pavel Machek 2016-11-11 8:25 ` Hans de Goede 2016-11-11 8:25 ` Hans de Goede 2016-11-10 17:55 ` Tony Lindgren 2016-11-10 17:55 ` Tony Lindgren 2016-11-10 20:29 ` Pavel Machek 2016-11-10 20:29 ` Pavel Machek 2016-11-10 21:34 ` Jacek Anaszewski 2016-11-10 21:34 ` Jacek Anaszewski 2016-11-11 12:01 ` Pavel Machek 2016-11-11 12:01 ` Pavel Machek 2016-11-11 17:03 ` Jacek Anaszewski 2016-11-11 17:03 ` Jacek Anaszewski 2016-11-11 19:28 ` Hans de Goede 2016-11-11 19:28 ` Hans de Goede 2016-11-11 22:12 ` Pavel Machek 2016-11-11 22:12 ` Pavel Machek 2016-11-12 8:03 ` Hans de Goede 2016-11-12 8:03 ` Hans de Goede 2016-11-13 9:10 ` Three different LED brightnesses (was Re: PM regression with LED changes in next-20161109) Pavel Machek 2016-11-13 9:10 ` Pavel Machek 2016-11-13 9:44 ` Hans de Goede 2016-11-13 9:44 ` Hans de Goede 2016-11-13 20:45 ` Pavel Machek [this message] 2016-11-13 20:45 ` Pavel Machek 2016-11-12 10:24 ` PM regression with LED changes in next-20161109 Jacek Anaszewski 2016-11-12 10:24 ` Jacek Anaszewski 2016-11-12 10:33 ` Hans de Goede 2016-11-12 10:33 ` Hans de Goede 2016-11-12 10:33 ` Hans de Goede 2016-11-12 19:14 ` Jacek Anaszewski 2016-11-12 19:14 ` Jacek Anaszewski 2016-11-12 21:14 ` Hans de Goede 2016-11-12 21:14 ` Hans de Goede 2016-11-13 11:44 ` Jacek Anaszewski 2016-11-13 11:44 ` Jacek Anaszewski 2016-11-13 13:52 ` Hans de Goede 2016-11-13 13:52 ` Hans de Goede 2016-11-14 9:12 ` Jacek Anaszewski 2016-11-14 9:12 ` Jacek Anaszewski 2016-11-14 9:12 ` Jacek Anaszewski 2016-11-14 12:51 ` Hans de Goede 2016-11-14 12:51 ` Hans de Goede 2016-11-15 10:01 ` Jacek Anaszewski 2016-11-15 10:01 ` Jacek Anaszewski 2016-11-15 10:09 ` Hans de Goede 2016-11-15 10:09 ` Hans de Goede 2016-11-15 10:31 ` LEDs that change brightness "itself" -- that's a trigger. " Pavel Machek 2016-11-15 10:31 ` Pavel Machek 2016-11-15 10:58 ` Jacek Anaszewski 2016-11-15 10:58 ` Jacek Anaszewski 2016-11-15 11:11 ` Pavel Machek 2016-11-15 11:11 ` Pavel Machek 2016-11-15 11:21 ` Hans de Goede 2016-11-15 11:21 ` Hans de Goede 2016-11-15 11:48 ` Pavel Machek 2016-11-15 11:48 ` Pavel Machek 2016-11-15 12:06 ` Hans de Goede 2016-11-15 12:06 ` Hans de Goede 2016-11-15 12:11 ` Pavel Machek 2016-11-15 12:11 ` Pavel Machek 2016-11-15 13:28 ` Jacek Anaszewski 2016-11-15 13:28 ` Jacek Anaszewski 2016-11-15 13:48 ` Hans de Goede 2016-11-15 13:48 ` Hans de Goede 2016-11-15 14:04 ` Jacek Anaszewski 2016-11-15 14:04 ` Jacek Anaszewski 2016-11-15 14:30 ` Hans de Goede 2016-11-15 14:30 ` Hans de Goede 2016-11-15 14:41 ` Jacek Anaszewski 2016-11-15 14:41 ` Jacek Anaszewski 2016-11-17 22:12 ` Hans de Goede 2016-11-17 22:12 ` Hans de Goede 2016-11-15 11:17 ` Hans de Goede 2016-11-15 11:17 ` Hans de Goede 2016-11-14 8:31 ` Pavel Machek 2016-11-14 8:31 ` Pavel Machek 2016-11-11 22:06 ` Pavel Machek 2016-11-11 22:06 ` Pavel Machek 2016-11-10 8:34 ` Hans de Goede 2016-11-10 8:34 ` Hans de Goede 2016-11-10 15:11 ` Tony Lindgren 2016-11-10 15:11 ` Tony Lindgren
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