Re: [PATCH] ide: Fix ata_id_has_dword_io to return DWORD I/O support properly

Alan Cox
2008-12-18T22:40:29Z

> OTOH the current patch is safe even for 2.6.28 (based on years of experience
> with the check that we had in IDE subsystem) and will fix some libata drivers
> (pata_legacy, pata_qdi and pata_winbond) to use dword IO on >= ATA-2 devices.
>
> [ In reality this a regression fix for IDE -> libata conversion as it is a
> huge performance improvement for the above mentioned DMA-less drivers. ]

The 32bit PIO support is already queued up and went to Jeff a while ago
so thats all in hand - its btw a big win on some suprising chipset cases
including Intel ICH chipsets.

> Jeff, I would like to merge it through IDE tree since the other patch depends
> on it but if you want to go ahead and push it to Linus earlier feel free to
> do it (or I can include it into the next IDE fixes pull request if you like).

Its still broken. You cannot use the version check for versions below 3.
I remain unconvinced we should be looking at it anywhere except specific
pure ISA cycle pass through hardware and thus it belongs as a helper for
those drivers not as ata_has_mumble stuff as its not ATA - eide_* maybe.

Doubly complicating it is the small detail that ATA1 devices don't
all respond to IDENTIFY in the first place....

Alan