On 11-05-03 11:07 AM, Alan Cox wrote:

On Tue, 03 May 2011 11:04:12 -0400
Mark Lord [off-list ref] wrote:

quoted

On 11-05-02 02:52 PM, Alan Cox wrote:

quoted

The queue depth and tag limits come from the SATA standard and also leak
fairly comprehensively into the AHCI spec so not unless the hardware has
extensions for it and is merely faked SATA (and if you are faking SATA
you have to wonder why if your goal is max performance)

The reason to "fake" SATA and/or ATA is unchanged since the 1990s:
so that the system BIOS can boot from the device, and the operating system
can work up to the point where it finally loads hardware-specific drivers.

The BIOS emulation is for legacy IDE style interfaces not AHCI.

I know that.  That's only half of it.