From mboxrd@z Thu Jan 1 00:00:00 1970 From: Randy Dunlap Subject: Re: [3/6] 2.6.21-rc4: known regressions Date: Wed, 28 Mar 2007 11:35:55 -0700 Message-ID: <20070328113555.c17bc1da.randy.dunlap@oracle.com> References: <1175065468.4017.1.camel@chaos> <200703281543.47049.maximlevitsky@gmail.com> <20070328180457.GA4253@mellanox.co.il> Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Return-path: In-Reply-To: <20070328180457.GA4253@mellanox.co.il> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: linux-pm-bounces@lists.linux-foundation.org Errors-To: linux-pm-bounces@lists.linux-foundation.org To: "Michael S. Tsirkin" Cc: jgarzik@pobox.com, Maxim , Jeff Chua , linux-ide@vger.kernel.org, Torvalds , gregkh@suse.de, linux-pm@lists.osdl.org, Linux Kernel Mailing List , Len@smtp.osdl.org, Adrian Bunk , linux-acpi@vger.kernel.org, linux-pci@atrey.karlin.mff.cuni.cz, "Eric W. Biederman" , Ingo Molnar , Jens Axboe , Thomas Gleixner , Linus@smtp.osdl.org, Andrew Morton List-Id: linux-pm@vger.kernel.org On Wed, 28 Mar 2007 20:04:57 +0200 Michael S. Tsirkin wrote: > > Subject : first disk access after resume takes several minutes > > ('date' does not advance after resume from RAM, CONFIG_NO_= HZ=3Dn) > > References : http://lkml.org/lkml/2007/3/8/117 > > http://lkml.org/lkml/2007/3/25/20 > > Submitter : Michael S. Tsirkin > = > ... > = > > Subject : after resume: X hangs after drawing a couple of windows > > References : http://lkml.org/lkml/2007/3/8/117 > > Submitter : Michael S. Tsirkin > > Status : unknown > = > ... > = > > > > > From: Jeff Chua > > > > > > It's related. I tested without CONFIG_HPET_TIMER, and now my X6= 0 can > > > > > > suspend and resume from RAM (s2ram). Even better, it works > > > > > > with/without CONFIG_NO_HZ. > > = > > Quoting Maxim : > > = > > Hi, > > I almost sure Iknow why this happens, > > The problem is that both hpet clock source > > and hpet clockevents doesn't have a suspend/resume function > > On resume we should enable the main counter _and_ enable > > legacy replacement mode, On my system main counter in > > enabled, by I think by bios, but legacy replacement mode is > > not, so if a system doesn't use lapic as a tick source, but > > use hpet+broadcast, it will hang for sure on resume, and i > > tested it > > = > > The patch below is a temporally fix, until > > clock-events and clocksources will get proper suspend/resume > > hooks: > > = > > Regards, > > Maxim Levitsky > = > Bingo! > = > The patch below fixes the two problems (listed above) with > resume from RAM that I have observed on my T60 with > 2.6.21-rc5: with this patch applied, and with CONFIG_NO_HZ > unset, date advances correctly, X functions properly and > there is no delay on first disk access. > = > Thanks very much. > = > --- > > Add suspend/resume for HPET > > Signed-off-by: Maxim Levitsky > = > Maxim, do you plan to send this upstream? with whitespace fixes, please... > Acked-by: Michael S. Tsirkin > = > --- > = > diff --git a/arch/i386/kernel/hpet.c b/arch/i386/kernel/hpet.c > index 0fd9fba..a1ec79e 100644 > --- a/arch/i386/kernel/hpet.c > +++ b/arch/i386/kernel/hpet.c > @@ -152,6 +152,16 @@ static void hpet_set_mode(enum clock_event_mode mode, > unsigned long cfg, cmp, now; > uint64_t delta; > = > + > + if ( mode !=3D CLOCK_EVT_MODE_UNUSED && mode !=3D CLOCK_EVT_MODE_SHUTDO= WN) > + { if (mode !=3D CLOCK_EVT_MODE_UNUSED && mode !=3D CLOCK_EVT_MODE_SHUTDOWN) { > + unsigned long cfg =3D hpet_readl(HPET_CFG); > + cfg |=3D HPET_CFG_ENABLE | HPET_CFG_LEGACY; > + hpet_writel(cfg, HPET_CFG); > + = delete above line. > + } > + = > + > switch(mode) { > case CLOCK_EVT_MODE_PERIODIC: > delta =3D ((uint64_t)(NSEC_PER_SEC/HZ)) * hpet_clockevent.mult; --- ~Randy *** Remember to use Documentation/SubmitChecklist when testing your code ***