From mboxrd@z Thu Jan  1 00:00:00 1970
From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Subject: Re: libata hotplug question
Date: Tue, 01 Dec 2009 16:30:09 +1100
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To: Tejun Heo <tj@kernel.org>
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On Tue, 2009-12-01 at 14:22 +0900, Tejun Heo wrote:
> Hello,
> 
> On 12/01/2009 02:17 PM, Benjamin Herrenschmidt wrote:
> > So I tried with implementing the link_online and link_offline callbacks
> > and it doesn't fly very high.
> > 
> > When I unplug the bay, it displays:
> > 
> > ata3: exception Emask 0x10 SAct 0x0 SErr 0x0 action 0xe frozen
> > ata3: EH complete
> 
> You didn't schedule any EH actions, right?

I did the usual ehi_hotplug + freeze

> libata-acpi.c does that.  Setting ATA_DFLAG_DETACH device flag and
> scheduling EH will do that.  Please take a look at
> ata_acpi_detach_device() but you must be *sure* that your hot unplug
> notification is completely reliable.

Well, it seems to be reliable that way for unplugs. I even debounce it
both ways but I'm actually considering removing the debounce on unplug.

I'll let you know how it goes with a custom prereset() that returns
-ENODEV. How would that differ from ATA_DFLAG_DETACH ?

Cheers,
Ben.