Re: [gentoo-user] AHCI/IDE-question

[Mike Edenfield]

On 1/21/2011 3:05 PM, meino.cramer@×××.de wrote:

>     solfire:/root>dmesg | grep -i ahci
>     ahci 0000:00:11.0: version 3.0
> *0* ahci 0000:00:11.0: PCI INT A -> GSI 19 (level, low) -> IRQ 19
> *1* ahci 0000:00:11.0: irq 78 for MSI/MSI-X
> *2* ahci 0000:00:11.0: AHCI 0001.0200 32 slots 6 ports 3 Gbps 0x3f impl SATA mode
> *3* ahci 0000:00:11.0: flags: 64bit ncq sntf ilck pm led clo pmp pio slum part

>     ahci 0000:07:00.0: PCI INT A -> GSI 44 (level, low) -> IRQ 44
> *4* ahci 0000:07:00.0: AHCI 0001.0000 32 slots 2 ports 3 Gbps 0x3 impl SATA mode
> *5* ahci 0000:07:00.0: flags: 64bit ncq pm led clo pmp pio slum part
> *6* ahci 0000:07:00.0: setting latency timer to 64

> For me bare eye this looks like the kernel ha switched all seven ports
> to AHCI.

To say that the kernel "switched" the ports is probably misleading.  The
kernel is just trying to hook up the devices it finds to the device
drivers it has available.

You told the kernel it was ok to use the AHCI driver.  The kernel
located those ports, detected that they supported the AHCI interface,
and thus, attached the AHCI SATA driver to them.  If you had told your
BIOS that those ports should be operated as IDE instead of AHCI, then
the kernel wouldn't have found any supported AHCI hardware and you
probably wouldn't be able to boot.

> Why is line *1* of the first block missing in the second block,
> Volker? Why is line *2* talking about "0x3f" while line  *4* is using
> "0x3", Volker? Why differ line *5* from line *3*, Volker? What does
> all these flags mean?

You could also dig into the internals of the libahci.c driver to figure
out what all of those display items mean.  In this case, your seeing two
different PCI busses with slightly different capabilities; just off the
top of my head, one is probably a 6-port PCI-X bus and the other a
2-port PCI bus, but I'd have to go look up the specs to your motherboard
to really find out.

--Mike