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Date: Mon, 20 Apr 2009 02:50:10 +0200 From: "Rafael J. Wysocki" <rjw@...k.pl> To: ncunningham-lkml@...a.org.au Cc: Russell King <rmk+lkml@....linux.org.uk>, Len Brown <lenb@...nel.org>, Linux Kernel List <linux-kernel@...r.kernel.org>, Linus Torvalds <torvalds@...ux-foundation.org>, pm list <linux-pm@...ts.linux-foundation.org>, ACPI Devel Maling List <linux-acpi@...r.kernel.org> Subject: Re: [PATCH] PM/Suspend: Introduce two new platform callbacks to avoid breakage (Re: 900af0d breaks some embedded suspend/resume) On Monday 20 April 2009, Nigel Cunningham wrote: > Hi. > > On Sat, 2009-04-18 at 20:47 +0200, Rafael J. Wysocki wrote: > > From: Rafael J. Wysocki <rjw@...k.pl> > > Subject: PM/Suspend: Introduce two new platform callbacks to avoid breakage > > > > Commit 900af0d973856d6feb6fc088c2d0d3fde57707d3 (PM: Change suspend > > code ordering) changed the ordering of suspend code in such a way > > that the platform .prepare() callback is now executed after the > > device drivers' late suspend callbacks have run. Unfortunately, this > > turns out to break ARM platforms that need to talk via I2C to power > > control devices during the .prepare() callback. > > > > For this reason introduce two new platform suspend callbacks, > > .prepare_late() and .wake(), that will be called just prior to > > disabling non-boot CPUs and right after bringing them back on line, > > respectively, and use them instead of .prepare() and .finish() for > > ACPI suspend. Make the PM core execute the .prepare() and .finish() > > platform suspend callbacks where they were executed previously (that > > is, right after calling the regular suspend methods provided by > > device drivers and right before executing their regular resume > > methods, respectively). > > > > It is not necessary to make analogous changes to the hibernation > > code and data structures at the moment, because they are only used > > by ACPI platforms. > > > > Signed-off-by: Rafael J. Wysocki <rjw@...k.pl> > > Reported-by: Russell King <rmk+kernel@....linux.org.uk> > > --- > > drivers/acpi/sleep.c | 8 ++++---- > > include/linux/suspend.h | 36 ++++++++++++++++++++++++++---------- > > kernel/power/main.c | 24 +++++++++++++++++------- > > 3 files changed, 47 insertions(+), 21 deletions(-) > > > > Index: linux-2.6/kernel/power/main.c > > =================================================================== > > --- linux-2.6.orig/kernel/power/main.c > > +++ linux-2.6/kernel/power/main.c > > @@ -291,20 +291,26 @@ static int suspend_enter(suspend_state_t > > > > device_pm_lock(); > > > > + if (suspend_ops->prepare) { > > + error = suspend_ops->prepare(); > > + if (error) > > + goto Done; > > + } > > + > > error = device_power_down(PMSG_SUSPEND); > > if (error) { > > printk(KERN_ERR "PM: Some devices failed to power down\n"); > > - goto Done; > > + goto Platfrom_finish; > > s/Platfrom/Platform > > Why retain the typo in multiple places? > > > } > > > > - if (suspend_ops->prepare) { > > - error = suspend_ops->prepare(); > > + if (suspend_ops->prepare_late) { > > + error = suspend_ops->prepare_late(); > > if (error) > > goto Power_up_devices; > > } > > Doesn't this invalidate testing that's already been done? Drivers > implementing prepare() (arm omap1, pxa, omap2, s3c and powerpc mpc52xx > and lite5200) are now going to have it called pre device_power_down. Why > not call the new prepare() "prepare_early" and leave the current prepare > as it is in the place where it's already called? Well, I wanted to avoid modifying platforms that were broken by the ordering change. > The name is also very confusing. Prepare matches with Finish and > Prepare_late with wake. How about prepare and unprepare? The names could be better as usual, but I'm going to revisit that shortly. > Reviewed-by: Nigel Cunningham <nigel@...onice.net> Thanks! Best, Rafael -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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