On 9/6/06, Greg Freemyer <greg.freemyer@xxxxxxxxx> wrote:
On 9/6/06, Siddharth Taneja <siddharth.taneja@xxxxxxxxx> wrote:
>
>
> On 9/6/06, Greg Freemyer <greg.freemyer@xxxxxxxxx > wrote:
> > On 9/5/06, Siddharth Taneja <siddharth.taneja@xxxxxxxxx> wrote:
> > > Hi,
> > >
> > > I have two SATA drives with an ICH6 SATA controller. I would like to
> know
> > > that if I were to operate the drives in PATA mode, what would happen if
> I
> > > enabled both ide/ata-piix and scsi/piix. I assume the drives would come
> up
> > > as both hda/hdb and sda/sdb. Is there a recommendation as to which
> device
> > > (or interface) to use?
> > >
> > > Also I set the bios settings for the SATA controller to AHCI and the
> > > ide/ata-piix driver is still able to bring up the drives as hde/hdg. Why
> is
> > > that? Shouldn't the ide/ata-piix realise that this is not a mode it
> > > supports?
> > >
> > > Thanks
> > >
> > > Siddharth
> > >
> > Siddharth,
> >
> > I don't know the specific answers, but this whole area is in a state of
> flux.
> > 2.6.16 likely behaves different from 2.6.17 , which is different from
> > 2.6.18, which will be different from 2.6.19.
> >
> > First, when multiple drivers are available for a single disk
> > controller, only one of them should be used. Using 2 or more can
> > cause huge conflicts that could easily destroy data.
> >
> > Most of the drivers are specifically written to avoid the issue. The
> > first driver that recognizes a disk controller claims the controller
> > and no other driver can claim it. In dual functionality controller
> > like the ICH6, I believe the 2 halves are claimed seperately. ie. The
> > PATA half can be controlled by drivers/ide and the SATA half can be
> > controlled by drivers/libata.
> >
> > That can be difficult to make work smoothly, so there is an ongoing
> > effort to do the below:
> > 2.6.18 - Greatly improved libata (SATA currently) Error Handling
> > 2.6.19 - Rename drivers/libata to drivers/ata as it is becoming the
> > main ATA driver
> > 2.6.19 - Add initial support for PATA drives to libata
> >
> > Thus when 2.6.19 comes out in a few months it will hopefully have the
> > ability to better handle these dual function controllers. It still
> > may require proper setup of config due to there still being multiple
> > drivers that support the same card.
> >
> > HTH
> > Greg
> > --
> > Greg Freemyer
> > The Norcross Group
> > Forensics for the 21st Century
> >
>
>
> Thanks for your answers Greg. I think I should disable the ide/ata-piix
> layer and only use my drives in the libata domain as it is becoming the
> standard in any case.
>
> So you think libata will completely replace the drivers/ide layer? I ask
> this because I have another platform with two PATA drives and an ICH5
> controller. Should I leave ide/piix enabled for that? (for accessing my
> drives in PATA mode). Or should I use the PATA functionality from the libata
> layer?
>
> Thanks
> Siddharth
>
There have been LKML posting explicitely stating that drivers/ide will
dissappear at some point in the future, but I suspect that will be a
year or two down the road.
With vanilla 2.6.17/18, I don't think there is much PATA support in
libata, but ICH5/6/7/8 may be special cases that are already supported
in libata bacuase of their popularity and dual nature. (-mm should
have had most of the PATA drivers for a couple months now, so you
could try -mm if your in the mood.)
As of a couple of days ago, the #upstream branch of the libata git
repository had a large number of new PATA/libata drivers added to it.
Alan Cox has been doing the rewrite for the last year or so.
The new PATA drivers have been in -mm for testing, etc. for a while I
believe and are currently slated to merge into 2.6.19 vanilla. The
recommendation in general is for users/distributions to use the older
drivers/ide drivers for a while yet. At some point I'm sure the new
drivers will be recommended, and eventually the old ones will be
deprecated, etc.
You may want to be aware of http://linux-ata.org/ as a libata status page.
It tends to only get updated a couple times a year, but it is better
than nothing.
Also, you may want to read the thread:
http://marc.theaimsgroup.com/?l=linux-ide&m=115736779014037&w=2
Especially the announcement e-mail. Lots of the follow e-mails relate
to dual booting between the drivers for testing. That may not have
any relevance for you.
HTH
Greg
--
Greg Freemyer
The Norcross Group
Forensics for the 21st Century
Thanks once again for your help. I think I'll give the PATA support from libata a try to see if the ICH5 stuff can work. I do remember reading that ICH5/6/7 were added in the libata layer.
Siddharth
