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

[Volker Armin Hemmann]

On Friday 21 January 2011 21:05:30 meino.cramer@×××.de wrote:
> Mark Knecht <markknecht@×××××.com> [11-01-21 20:36]:
> > On Fri, Jan 21, 2011 at 11:16 AM, Volker Armin Hemmann
> > <volkerarmin@××××××××××.com> wrote:
> > <SNIP>
> >
> > >>    I'm happy to be corrected (by Volker I'm sure) but that's my
> > >> guess
> > >> as to what you're seeing.
> > >
> > > you are confusing bios calls and bios programming chips as.... also
> > > - is there any good reason to use IDE mode? Any? At all?
> >
> > I don't believe I'm 'confusing bios calls with bios programming'. The
> > BIOS can do whatever it wants to in programming the chips as long as
> > grub can still find the kernel. After grub finds the kernel the kernel
> > is free to override whatever chip programming the BIOS has done and
> > reprogram the chips as it sees best.
> >
> > I think the issue meino possibly has is that he likely didn't include
> > an Int13 type driver in the kernel or most likely his system would
> > have booted like it did in the _very_ old days.
> >
> > I agree that there isn't any good reason I know of to use IDE mode
> > unless the other modes the BIOS provides don't work.
> >
> > I cannot get into my Asus BIOS at the moment, but as I remember it
> > Asus gave me something like
> >
> > IDE
> > AHCI
> > AHCI + compatibility
> >
> > IIRC I had to use the last one to get mine to boot but I may be wrong
> > about that. I only mention this as meino is also using Asus so he
> > might look for similar options.
> >
> > - Mark
>
> Hi,
>
> I switched the BIOS from IDE (kernel is using AHCI) to AHCI (kernel
> uses AHCI). The dmesg says (I did a dmesg | grep -i ahci now, previous
> check was done with dmesg | grep AHCI only):
>
>     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 scsi0 : ahci
>     scsi1 : ahci
>     scsi2 : ahci
>     scsi3 : ahci
>     scsi4 : ahci
>     scsi5 : ahci
>     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
>     scsi6 : ahci
>     scsi7 : ahci
>
> For me bare eye this looks like the kernel ha switched all seven ports
> to AHCI. Lines marked with "*n*" are still a riddle to me. May be
> Volker will give us some enlightment?
> 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 know - there are websites for that. Google is your friend. But even a 
glance would reveal to you:
two different chips.
One using MSI for interrupts the second not.

> I find this interesting:
>
> http://www.linuxquestions.org/questions/linux-hardware-18/6-tips-for-improvi
> ng-hard-drive-performance-835034/

it is a start. But the first link there... just saying.. there is no magically 
correct value for stride or chunk.

Oh and if you are using AFT drives make sure the partitions are set up 
correctly.

Also:
https://ata.wiki.kernel.org/index.php/Main_Page