From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pavel Machek Subject: Re: comments on irc log Date: Sat, 19 Mar 2005 00:18:01 +0100 Message-ID: <20050318231801.GE24449@elf.ucw.cz> References: <1111187278.1236.187.camel@gaston> Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="===============95215026343470877==" In-Reply-To: <1111187278.1236.187.camel@gaston> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: linux-pm-bounces-qjLDD68F18O7TbgM5vRIOg@public.gmane.org Errors-To: linux-pm-bounces-qjLDD68F18O7TbgM5vRIOg@public.gmane.org To: Benjamin Herrenschmidt Cc: Linux-pm mailing list List-Id: linux-pm@vger.kernel.org --===============95215026343470877== Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Hi! > > Usually very fast. Unfortunately for some kinds of USB host controllers > > it can be relatively slow, since quiescing the controller has an > > unavoidable side effect of suspending all devices on the bus. > > I wonder if we need to quiesce the controller in fact for FREEZE. > Probably not. Just stop all queue processing and refuse URBs. The hcca > will still get updated, but who cares ? it will end up beeing saved in > an inconsistent state in the suspend image, so what ? On resume, we will > have rebooted, we can "clean it up". > > This is sort-of breaking the rule of "no DMA", and thus is not suitable > for kexec (which is ok, kexec currently uses the separate "shutdown" > callback which must switch DMA off), but would fix the problem for > suspend to disk... What problem? suspend seems to +/- work with suspend-to-disk just now. I'd really hate to have to think about "some memory may change behind my back" during suspend. I think "no DMA" is a good rule. Pavel -- People were complaining that M$ turns users into beta-testers... ...jr ghea gurz vagb qrirybcref, naq gurl frrz gb yvxr vg gung jnl! --===============95215026343470877== Content-Type: text/plain; charset="iso-8859-1" MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Disposition: inline --===============95215026343470877==--