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  PHC 
Open Source and information security mailing list archives
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date:	Sun, 20 Dec 2009 13:55:45 +0100
From:	"Rafael J. Wysocki" <>
To:	Alan Stern <>
Cc:	Linus Torvalds <>,
	Zhang Rui <>,
	LKML <>,
	ACPI Devel Maling List <>,
	pm list <>
Subject: Re: Async suspend-resume patch w/ completions (was: Re: Async suspend-resume patch w/ rwsems)

On Sunday 20 December 2009, Alan Stern wrote:
> On Sat, 19 Dec 2009, Rafael J. Wysocki wrote:
> > On Friday 18 December 2009, Alan Stern wrote:
> > > On Fri, 18 Dec 2009, Rafael J. Wysocki wrote:
> > > 
> > > > I didn't manage to do that, but I was able to mark sd and i8042 as async and
> > > > see the impact of this.
> > > 
> > > Apparently this didn't do what you wanted.  In the nx6325
> > > sd+i8042+async+extra log, the 0:0:0:0 device (which is a SCSI disk) was
> To be precise, the device is an ATA or SATA disk but it is managed by 
> the sd driver.
> > > suspended by the main thread instead of an async thread.
> > 
> > Hm, that's odd, because there's a noticeable time difference between the
> > two cases in which the sd is sync and async.  I'll look into it further.
> I don't know what the whole story is, but the PID number tells the 
> tale.
> > > There's an important point I neglected to mention before.  Your logs 
> > > don't show anything for devices with no suspend callbacks at all.  
> > > Nevertheless, these devices sit on the device list and prevent other
> > > devices from suspending or resuming as soon as they could.
> > 
> > Unless they are async, that is.
> Yes.  It would be simpler to make them async.  But first we ought to
> know what they are.  Can you add an extra line to the log for such
> devices?

Sure, I'll do that.

> What I'm afraid of is that there might be a "normal" device with a
> "normal" ancestor but with "abnormal" devices in between (where
> "normal" means there is a suspend or resume routine and "abnormal"  
> means all the method pointers are NULL).  I know that this happens when
> there's a USB mass-storage device, for example.  If we complete the
> intermediate devices immediately, then there won't be anything to
> prevent the ancestor from suspending before the device or the device
> from resuming before the ancestor.

I'm afraid of that too.

To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to
More majordomo info at
Please read the FAQ at

Powered by blists - more mailing lists