Re: USB harddisk drive fails on 2.6.23-rc3 (regression)

Hi Alan,

On Mon, 20 Aug 2007 10:08:52 -0400 (EDT), Alan Stern wrote:
> On Sun, 19 Aug 2007, Jean Delvare wrote:
> 
> > > There are lots of possible ways to address this.  Worth trying is
> > > to enable the "allow_restart" attribute for the drive.  The attribute
> > > file appears in the sysfs directory for the disk; you may have to
> > > search around a little to find exactly where it is.  Also you may have
> > > to use the blockdev command to force the system to read the partition
> > > table after turning on allow_restart.
> > 
> > Yes, that worked. After writing 1 to allow_restart and running
> > "blockdev --rereadpt /dev/sda", the partition table can be read with
> > "fdisk -l /dev/sda" again.

For the records, running blockdev wasn't even needed.

> > Am I supposed to add these commands to my init scripts, or is there
> > another way to make the effect permanent?
> 
> If allow_restart were set to to 1 by default then you wouldn't have to 
> do anything.  That's why I wrote:
> 
> > > (Perhaps allow_restart should be on by default for all SCSI devices.  
> > > That's a question which should be raised on the linux-scsi mailing 
> > > list.)
> 
> I can't see any reason for not setting it to 1 by default, but there 
> may be reasons I am not aware of.

This approach would indeed be preferred over Oliver's blacklist entry,
as I still get the power saving with allow_restart=1, while I
(obviously) lose it with the blacklist entry.

> The errors you've been getting are from the USB-IDE interface, saying 
> that it has spun down the disk and the disk needs to be spun up again 
> before it can be used.  Now perhaps you can tell whether the disk 
> really _has_ been spun down -- hardware lies about this sort of thing 
> all the time.

The external hard disk drive actually spins down after some time, and
up again when being accessed. I can hear it, and I'd say this is a
pretty good idea, especially for my use case. I wish I could tweak the
timeout though, as it's a bit too quick IMHO (30 seconds or so).

> If the disk really was spun down, or even if it wasn't but you use the
> disk a lot and you don't like the extra overhead added by the
> autoresume-error-spinup-retry sequence, then you would of course want
> to prevent the drive from autosuspending unless it was going to be idle
> for a reasonably long time.  In other words, you would want to increase
> the autosuspend delay.

I mean to use this drive for weekly backups only, so I do want the
drive to autosuspend if possible. Not sure about the optimal delay
though, time will tell.

Thanks for your help and useful explanations.

-- 
Jean Delvare

-------------------------------------------------------------------------
This SF.net email is sponsored by: Splunk Inc.
Still grepping through log files to find problems?  Stop.
Now Search log events and configuration files using AJAX and a browser.
Download your FREE copy of Splunk now >>  http://get.splunk.com/
_______________________________________________
[email protected]
To unsubscribe, use the last form field at:
https://lists.sourceforge.net/lists/listinfo/linux-usb-devel