From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pavel Machek Subject: Re: RE: on-ness Date: Mon, 24 Apr 2006 23:32:45 +0200 Message-ID: <20060424213245.GP3386@elf.ucw.cz> References: <20060421183340.GA3071@isilmar.linta.de> <20060421190121.GB2078@elf.ucw.cz> <200604241404.41122.david-b@pacbell.net> Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="===============20744884561816002==" Return-path: In-Reply-To: <200604241404.41122.david-b@pacbell.net> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: linux-pm-bounces@lists.osdl.org Errors-To: linux-pm-bounces@lists.osdl.org To: David Brownell Cc: linux-pm@lists.osdl.org, Dominik Brodowski List-Id: linux-pm@vger.kernel.org --===============20744884561816002== Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Po 24-04-06 14:04:40, David Brownell wrote: > > > > > > Uh. Not /sys/power/state. But /sys/devices/...../power/{[a],[b],[c]} where > > > > > [a], [b] and [c] need sensible names. > > > > > > > > Well, "on" could have one defined meaning. Maybe it's the only option > > > > available, until drivers add intelligence. I don't see any problem > > > > with the other names being system-specific, since it's rather unlikely > > > > that a PCI_D3hot state will ever appear on most embedded ARM boxes. > > > > And if any userspace code tries to set power states, it had darn well > > > > better understand exactly what's going on. > > > > > > Yes. However if a network managing userspace code wants to set the power > > > conusmption of a WLAN device to the lowest possible setting, it shouldn't > > > need a configuration file specific for each platform. > > > > I'd say that "on" and "off" are well defined. > > Are they? Does "off" imply the device will have been reset the next > time it goes to "on"? If not, there would seem to be two "off" states. > Or maybe more ... PCI_D0 is probably "on", but all of the other PCI > device states seem to be variants of "off", not of "on". I'd say "off" is as low as possible, perhaps including device reset. > And for that matter, "on" doesn't seem to me to imply anything more > than "full functionality from external POV". That doesn't necessarily > imply "full power-on", and in fact it'd be better if it were using the > lowest power state(s) available. That state might be compatible with > certain system sleep states, or not, depending on the device's > workload. Agreed. > > For certain classes (like ethernet), other states may be common > > between platforms, too, like "off-with-WOL". > > Actually the wakeup characteristics are orthogonal, there are per-device > bits controlling whether a device can and should do the wakeup. We don't > for example treat "PCI_D3hot with wakeup" as a distinct state. Ok, "off-with-WOL" was example. Hopefully there's better example. Pavel -- Thanks for all the (sleeping) penguins. --===============20744884561816002== Content-Type: text/plain; charset="iso-8859-1" MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Disposition: inline --===============20744884561816002==--