From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pavel Machek Subject: Re: [RFC][PATCH] swsusp: warn about USB devices in documentation Date: Mon, 20 Feb 2006 17:43:10 +0100 Message-ID: <20060220164309.GC19156@elf.ucw.cz> References: <20060220163707.GA19156@elf.ucw.cz> Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="===============10927611614120769==" Return-path: In-Reply-To: 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: Alan Stern Cc: Linux PM List-Id: linux-pm@vger.kernel.org --===============10927611614120769== Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Po 20-02-06 11:41:49, Alan Stern wrote: > On Mon, 20 Feb 2006, Pavel Machek wrote: > > > Hi! > > > > > Can you update the patch to fix this paragraph? > > > > > > > > Well, this is talking about suspend-to-disk... That is expected to > > > > power down machine, without providing USB bus power. If box > > > > suspends-to-disk and leaves USB up, something is wrong with the > > > > machine. > > > > > > Oh, sorry, I didn't realize that. > > > > > > Isn't there an ACPI mode that powers down most things (including RAM) but > > > is able to respond to wakeup events? I can't remember the mode's name, > > > except that it's almost certainly "S" followed by some meaningless number > > > followed by some unhelpful word. :-) Since USB plug/unplug is potentially > > > a wakeup event, such a mode must provide suspend power to the USB > > > controller. > > > > Maybe S4 does that, but I'm not sure... > > > > > Does swsusp still support these not-completely-powered-off modes? > > > > Yes. echo platform > /sys/power/disk. > > So if you did that, you could suspend-to-disk while leaving USB up, right? > Without anything being wrong with the machine. Not sure... never seen such machine. My impression is that USB needs more power than RAMs in self-refresh mode... You are right that maybe some machines where USB has power in S4 exist.. I never seen one. Pavel -- Web maintainer for suspend.sf.net (www.sf.net/projects/suspend) wanted... --===============10927611614120769== Content-Type: text/plain; charset="iso-8859-1" MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Disposition: inline --===============10927611614120769==--