Re: [PATCH 2.6.22] remove Intel combined mode quirk

[Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>]

On Friday 09 March 2007, Jeff Garzik wrote:
> 
> Discussed for 2.6.21, but pushed back because the current SATA code
> had enough fun stuff to debug already.  Thus, just queued the following
> for 2.6.22 in libata-dev.git#upstream.
> 
> The nasty ____request_resource hack is finally gone.
> 
> In practical terms, this usually means that some combined mode users
> will have their SATA devices driven by the old-IDE driver rather than
> libata (because old-IDE is often non-modular, and thus probes first).
> 
> But really, these same users will IMO cheer the removal of the
> performance-killing split-driver configuration, so its a net win.
> And the code is smaller and more clean, with one less special case
> hack.
> 
>     libata/IDE: remove combined mode quirk
>     
>     Both old-IDE and libata should be able handle all controllers and
>     devices found using normal resource reservation methods.
>     
>     This eliminates the awful, low-performing split-driver configuration
>     where old-IDE drove the PATA portion of a PCI device, in PIO-only mode,
>     and libata drove the SATA portion of the /same/ PCI device, in DMA mode.
>     Typically vendors would ship SATA hard drive / PATA optical
>     configuration, which would lend itself to slow (PIO-only) CD-ROM
>     performance.
>     
>     For Intel users running in combined mode, it is now wholly dependent on
>     your driver choice (potentially link order, if you compile both drivers
>     in) whether old-IDE or libata will drive your hardware.
>     
>     In either case, you will get full performance from both SATA and PATA
>     ports now, without having to pass a kernel command line parameter.
>     
>     Signed-off-by: Jeff Garzik <jeff@garzik.org>

Acked-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

Thanks for fixing this.

Bart