linux-kernel - Re: [linux-pm] Re: [PATCH 3/3 -mm] kexec based hibernation -v6: kexec hibernate/resume

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Tue, 20 Nov 2007 09:58:12 -0500 (EST)
From:	Alan Stern <stern@...land.harvard.edu>
To:	"Huang, Ying" <ying.huang@...el.com>
cc:	"Rafael J. Wysocki" <rjw@...k.pl>, <nigel@...el.suspend2.net>,
	Kexec Mailing List <kexec@...ts.infradead.org>,
	<linux-kernel@...r.kernel.org>,
	"Eric W. Biederman" <ebiederm@...ssion.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	<linux-pm@...ts.linux-foundation.org>,
	Jeremy Maitin-Shepard <jbms@....edu>
Subject: Re: [linux-pm] Re: [PATCH 3/3 -mm] kexec based hibernation -v6:
 kexec hibernate/resume

On Tue, 20 Nov 2007, Huang, Ying wrote:

> - What is the difference between PMSG_SUSPEND and PMSG_FREEZE?

SUSPEND means that the system is about to go into a low-power state, so 
the driver should take the appropriate action to reduce the device's 
power consumption.  It should also stop all I/O and DMA to the device.  
Interrupts can remain enabled if the device is supposed to be a wakeup 
source; otherwise they should be disabled.

FREEZE means that the system is going to hibernate, and devices need to
be quiescent (no I/O, no DMA, and no interrupts) so that an atomic
memory snapshot can be captured.  The driver should take the
appropriate action to quiesce the device but the power level doesn't
need to change.

PRETHAW means that the system is going to resume from hibernation by
loading a previously-saved memory snapshot.  The driver should take the
appropriate action to quiesce the device (no I/O, no DMA, and no
interrupts) so that the snapshot can be safely restored, but the power
level doesn't need to change.  The driver may also want to put the
device into a special state so that the saved kernel's resume method
will recognize the device has undergone a hibernation cycle and needs
to be reinitialized.

Alan Stern

-
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/