Re: Linux v2.6.22-rc3

[Bill Davidsen <davidsen@tmr.com>]

Jeff Garzik wrote:

> Several people have reported LITE-ON LTR-48246S detection failed
> because SETXFER fails.  It seems the device raises IRQ too early after
> SETXFER.  This is controller independent.  The same problem has been
> reported for different controllers.
> 
> So, now we have pata_via where the controller raises IRQ before it's
> ready after SETXFER and a device which does similar thing.  This patch
> makes libata always execute SETXFER via polling.  As this only happens
> during EH, performance impact is nil.  Setting ATA_TFLAG_POLLING is
> also moved from issue hot path to ata_dev_set_xfermode() - the only
> place where SETXFER can be issued.
> 
> Note that ATA_TFLAG_POLLING applies only to drivers which implement
> SFF TF interface and use libata HSM.  More advanced controllers ignore
> the flag.  This doesn't matter for this fix as SFF TF controllers are
> the problematic ones.
> 
Not only kills two birds with a single store, but will avoid having to 
re-solve the problem at sometime in the future. That's good software!

-- 
Bill Davidsen <davidsen@tmr.com>
   "We have more to fear from the bungling of the incompetent than from
the machinations of the wicked."  - from Slashdot