hot plugging eSATA

[Lennart Sorensen]

On Thu, Apr 29, 2010 at 03:35:47PM -0400, D. Hugh Redelmeier wrote:
> | Like XP.
> | 
> | And intel has been an ass in that they only provide AHCI drivers for
> | their older chipsets (like yours) if it is the R version (so ICH9R has
> | AHCI drivers, ICH9 does not).
> 
> My machine came with Vista.  I booted into Vista last night.  During
> the boot process, it rebooted (back to POST screen and then grub).  On
> the second boot, it claimed that I should go into a recovery mode.  It
> offered to restore my whole system (probably losing my Linux
> partitions), so I declined.  It suggested that I might have installed
> a new device and that I should undo this.
> 
> Then I remembered that I'd changed this BIOS setting nearly three
> weeks ago, so I reversed it and was able to boot Vista.
> 
> - what a horrible symptom
> 
> - why would Vista not support AHCI.  Especially since the Vista was
>   provided (forced on me) by the hardware vendor (HP).
> 
> A solution was provided in Microsoft Knowledge Base 922976.  Almost.
> I used Vista's regedit to change two keys.  (The KB suggests either
> would do; just doing one didn't work but two did.)  So the driver is
> capable, just not willing to try without a wacky nudge.

Windows does NOT appriciate driver changes like that.  Changing your
SATA controller to AHCI changes the PCI id, the driver needed, and in
fact the whole interface to the disk is changed.  Windows has no reason
to think it needs to load the AHCI driver, so it fails.  If you had
somehow installed the driver and convinced it that it should load
that driver on next boot, then it ought to work.  That's likely what
the registry key did.  Or if you had reinstalled it from scratch after
changing the bios it would probably have detected the disk fine and been
happy too.

Having just read the KB article, that is exactly what the registery change
does.  It tells windows to load that driver at boot, which makes it work.

Linux systems often try a lot more drivers at boot rather than just the
ones matching previously detected hardware.  Some would say linux is
wasting valuable boot time, others consider linux to be more robust to
hardware changes.

-- 
Len Sorensen
--
The Toronto Linux Users Group.      Meetings: http://gtalug.org/
TLUG requests: Linux topics, No HTML, wrap text below 80 columns
How to UNSUBSCRIBE: http://gtalug.org/wiki/Mailing_lists