Rafael J. Wysocki wrote:
quoted text
> On Saturday, July 10, 2010, Stephan Diestelhorst wrote:
> > Rafael J. Wysocki wrote:
> > > On Friday, July 09, 2010, Stephan Diestelhorst wrote:
> > > > I wrote:
> > > > >   I have an issue with suspend to RAM and I/O load on a disk. Symptoms
> > > > > are that the disk does not respond to requests when woken up, producing
> > > > > only I/O errors on all tested kernels (newest 2.6.35-rc4 (Ubuntu
> > > > > mainline PPA build)):
> > > > > 
> > > > <snip>
> > > >  
> > > > > This can be triggered most reliably with multiple "direct" writes to
> > > > > disk, I create the load with the attached script. If the issue is
> > > > > triggered, suspend (through pm-suspend) takes very long.
> > > > 
> > > > > IMHO the interesting log output during suspend is:
> > > > > [ 1674.700125] ata1.00: qc timeout (cmd 0xec)
> 
> I have a box where this problem is kind of reproducible, but it happens _very_
> rarely.  Also I can't reproduce it on demand running suspend-resume in a tight
> loop.  Are you able to reproduce it more regurarly?

For me it is much more reproducible. If I run multiple direct writing
dd-s to the disk in question I trigger it rather reliably (~75% or
higher). See the attached script from an earlier email.
Maybe that helps triggering your case more reliabl, too?

quoted text
> Also, what kind of disk do you use?

It is a Samsung HM321HI in a Samsung Eikee R525 notebook, please also 
see my smartctl -a log, attached earlier.

Interesting, I have a similar symptom on one of my home servers,
which has a *Samsung* SpinPoint F1 and it went away with different
disks. So maybe these disks are either faulty themselves or they
trigger the issue more often?

I also have a LVM on top of LUKS on the disk. So the I/O will also
add some computational overhead for encryption.

Stephan
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