Re: Serial ATA (SATA) for Linux status report

From: Samuel Flory
Date: Wed Dec 03 2003 - 20:01:07 EST


Jeff Garzik wrote:
Andre Tomt wrote:

On Wed, 2003-12-03 at 21:44, Jeff Garzik wrote:

Intel ICH5
----------
Summary: No TCQ. Looks like a PATA controller, but with a few added,
non-standard SATA port controls.


One question - with "including hotplug", does that mean some set hotplug
standard? Reason I'm asking is, we have a few servers from SuperMicro,
with a ICH5R S-ATA controller that claims it's supporting hotplug, but
hotplug is not in your ICH5-summary.


Alas, there is no hotplug support in the ICH5 or ICH5-R SATA hardware.

One could argue there is "coldplug" support in that hardware -- disable the entire interface, including any active devices, then re-enable and re-scan -- but it's a bit of a hack. If there's enough demand, I could write some code for that. It would involve something like

# /sbin/sata off
{ plug in or remove a device }
# /sbin/sata on

You really, really, really don't want to actually unplug a SATA drive while it's active, on ICH5 hardware.


In theroy the scsi driver allows you kill a drive, and do rescan by echoing to /proc/scsi.scsi. I know it worked under 2.4 with sca drive on a hotswap backplane. This was over a year ago. So it may have been broken.

scsi.c:
* Usage: echo "scsi add-single-device 0 1 2 3" >/proc/scsi/scsi
* with "0 1 2 3" replaced by your "Host Channel Id Lun".


/*
* Usage: echo "scsi remove-single-device 0 1 2 3" >/proc/scsi/scsi
* with "0 1 2 3" replaced by your "Host Channel Id Lun".
*

PS- Yes I know says it isn't for hotswap, and that it's prebeta. This comment dates back to at least 2.2. It's worked for least 4 years.
--
There is no such thing as obsolete hardware.
Merely hardware that other people don't want.
(The Second Rule of Hardware Acquisition)
Sam Flory <sflory@xxxxxxxxxxxx>

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/