Re: Changes to ide-probe.c in 2.6.9-rc2 causing improper detection

[Jeff Garzik <jgarzik@pobox.com>]

Mark Lord wrote:
> One obvious safeguard would be to never use FLUSH_CACHE on any
> drive that lacks UDMA, unless the drive claims to support FLUSH_CACHE.
> 
> That will eliminate all current FLASH memory devices.

I think you're hunting for hueristics, not making a general rule.  IMO 
any assumption that this behavior will always be limited to flash 
devices is a shaky assumption.

Your initial suggestion is probably much better:
> But one could augment it with a check of the ATA revision code,
> and possibly exclude drives that predate the *formal* introduction
> of the FLUSH_CACHE command, unless their IDENTIFY data specifically
> claims to include it. 

That implies my code would become

	if (ata version < 4)
		return not-supported
	if (wbcache-enabled or have-flush-cache or have-flush-cache-ext)
		return supported
	return not-supported

Yes?

Alan, do you still feel that the "wbcache-enabled" test should be removed?

Since wbcache-enabled is more of a hueristic than a formal test, I don't 
mind removing it.

	Jeff