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* Libata for parallel ATA controllers
@ 2005-09-22 17:05 Alan Cox
  2005-09-23  2:24 ` Mark Lord
  0 siblings, 1 reply; 3+ messages in thread
From: Alan Cox @ 2005-09-22 17:05 UTC (permalink / raw)
  To: linux-kernel


I mentioned a while ago I was hacking on libata and PATA drivers. I've
also fed a few bits of the needed support code to Jeff Garzik as I went.

Some initial patches are now ready for wider testing although strictly
suicide squad material at this point. I'm now at the point I'm running a
full Fedora Core 4 with CONFIG_IDE=n using four disk raid on SIL680
controllers.

A lot of hardware isn't yet covered - I'm working on adding more support
but I wanted to start with weirder devices first to better understand
what was needed in libata.

Status info and patches are at

http://zeniv.linux.org.uk/~alan/IDE


Enjoy but remember this is very early code and don't use it for
production!


^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: Libata for parallel ATA controllers
  2005-09-22 17:05 Libata for parallel ATA controllers Alan Cox
@ 2005-09-23  2:24 ` Mark Lord
  2005-09-23 12:07   ` Alan Cox
  0 siblings, 1 reply; 3+ messages in thread
From: Mark Lord @ 2005-09-23  2:24 UTC (permalink / raw)
  To: Alan Cox; +Cc: linux-kernel

Alan Cox wrote:
>
> Status info and patches are at
> 
> http://zeniv.linux.org.uk/~alan/IDE
> 
> Enjoy but remember this is very early code and don't use it for
> production!

And especially keep in mind, that libata has practically *no*
built-in error-handling or recovery mechanisms yet.  If a drive
gets into a "reset me to recover" state, then libata just might
require a reboot to recover, whereas the IDE subsystem will usually
try a reset operation at some point.

Not a problem with modern, mostly bug-free hardware (eg. most SATA),
but this could be an issue for some PATA interfaces.

Cheers


^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: Libata for parallel ATA controllers
  2005-09-23  2:24 ` Mark Lord
@ 2005-09-23 12:07   ` Alan Cox
  0 siblings, 0 replies; 3+ messages in thread
From: Alan Cox @ 2005-09-23 12:07 UTC (permalink / raw)
  To: Mark Lord; +Cc: linux-kernel

On Iau, 2005-09-22 at 22:24 -0400, Mark Lord wrote:
> built-in error-handling or recovery mechanisms yet.  If a drive
> gets into a "reset me to recover" state, then libata just might
> require a reboot to recover, whereas the IDE subsystem will usually
> try a reset operation at some point.

Or crash.

> Not a problem with modern, mostly bug-free hardware (eg. most SATA),
> but this could be an issue for some PATA interfaces.

The basic error handling in the libata code seems to work as well when I
tested it, if not better because the old PATA code hangs the box on SMP
or pre-empt if you get a DMA timeout and cable changedown due to locking
flaws and also issues an immediate idle in error recovery which seems to
crash some drives for good.

What doesn't work at all is failed cable detect - the speed change down
support simply isn't in libata yet and that turns a downspeed change for
poor cables or cable misdetect into a hang.



^ permalink raw reply	[flat|nested] 3+ messages in thread

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