hdx to sdx change in 2.6.28

alupu alupu02 at gmail.com
Sat Jan 24 17:23:21 PST 2009


Hi Simon,

On Sat, Jan 24, 2009 at 6:07 AM, Simon Geard wrote:
> On Wed, 2009-01-14 at 21:15 -0500, alupu wrote:
>> - QUESTION
>> Does anybody know anything about the transition to 2.6.28 changing the
>> "view" of the system to a "Universal", "Uniform", "Consistent", "SATA
>> centric", etc.?

> Disclaimer - I'm speaking only as someone who uses this stuff, not as
> any kind of kernel expert.

I don't know about that, but your comments are _very_ informative.
Many thanks.

> Shortly after SATA drives started coming out, the kernel developers
> started work on a new framework for hard-drive access, called libATA -
> it's not SATA centric as such, but it was created to make supporting
> SATA easier, and to remedy deficiencies in the old system. Because of
> that, almost all SATA drivers use this framework, but they've also been
> working on replacing old PATA drivers with new ones for the new
> framework.
>
> As with the usb-storage framework for dealing with flash drives and
> stuff, this new framework uses a lot of infrastructure that came
> originally from SCSI, hence the change in device names to sdX.
>
> As to why things have suddenly broken for you, I'm only guessing, but
> I'd say 2.6.28 must have removed the old driver you were using - maybe
> the Changelog has some mention of it?

1. First a correction with accompanying apology:
Alex originally wrote:
"System works as expected (i.e., just fine) on 2.6.27
(actually up to 2.6.27.4;  haven't tested .5 - .10;  assume similar)"
As mentioned, I jumped directly to 2.6.28 from 2.6.27.4.  Silly me.
As fate would have it, in retrospect, things would have "broken" for me
in the very next release, 2.6.27.5!
Maybe this is why (B)LFS people (who are as of this writing at 2.6.27.8)
ignored my thread "hdx to sdx change in 2.6.28" for all this time as
just one of them "suspicious header" messages. :)
And, BTW, there's even a 2.6.27.12!
Another BTW:
>From .5 to .12 the entry "SiS PATA support" is labeled "(experimental)".
Starting with 2.6.28 (we're at 2.6.28.1), it's just that.

2. As for the ChangeLog, there's no mention of the "change" in 2.6.27.5.
Luckily, 2.6.27.5 has only 59 commits.  Imagine what I went through
with 2.6.28 which contains 9784!
Granted, it's possible there was some talk about the new "framework"
in pre-2.6.27.5, since in 2.6.27.4 there were already several
"... PATA support" entries such as "VIA PATA support".
For the record, I searched on "SiS", "support", "experimental", etc.

3. "[they] must have removed the old driver you were using ..."
Unfortunately, I'm not at the subject PATA machine now, but I'm 99.9%
sure that selecting the fateful "SiS PATA support" was an absolute must
before all the machinations with GRUB and fstab fields in order to
penetrate the "Kernel panic" wall.
However. that leaves a nagging .1% grain of salt, meaning if I had
futzed a little bit more with just GRUB and fstab, I'd've managed
to fix things without needing "SiS PATA support" enabled.
That is, to know conclusively whether the reason for the break was
their pulling "the old driver" right from under me, or something else.

4. Sure, everybody would die to know exactly the details of "libATA"
and all but what bothers me more is somehow spelled in the original
question, why the quiet
"... transition to 2.6.28 changing the 'view' ...".
True, my problems of having to change from hdx to sdx don't amount
to a hill of beans in this crazy world but in our "little" universe
of Linux where according to folklore the average user is still at
386SX and 256kB (P)ATA drives, this "transition" certainly appears
considerably a bigger event than some commits - while perfectly
honorable - like "sata_nv: fix generic, nf2/3 detection regression".

4.1. As noted, some LFS folks should be at 2.6.27.8.
A sub-question would then be, how come nobody got hit with this
"transition".  Could they perchance be all pure-SATA?  Or diskless?
Have I missed  another relevant support thread?

Thanks again for your helpful comments.
-- Alex



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