Re: 2.6.16-rc4: known regressions

[Jens Axboe <axboe@suse.de>]

On Wed, Feb 22 2006, Greg KH wrote:
> On Wed, Feb 22, 2006 at 09:45:08PM +0100, Jens Axboe wrote:
> > On Wed, Feb 22 2006, Greg KH wrote:
> > > On Wed, Feb 22, 2006 at 08:29:48PM +0100, Arjan van de Ven wrote:
> > > > On Wed, 2006-02-22 at 11:18 -0800, Greg KH wrote:
> > > > > What about trying a stock 2.6.6 or so kernel?  Does that work
> > > > > differently from 2.6.15?
> > > > 
> > > > ... however it's very much designed only for the kernel that comes with
> > > > it (with "it's" I mean all the userspace infrastructure); all the
> > > > changes and additions since 2.6.9 aren't incorporated so you probably
> > > > really want new alsa, new initscripts, new mkinitrd, new
> > > > module-init-tools. some because of abi changes since 2.6.9, others
> > > > because the kernel grew capabilities that are really needed for "nice"
> > > > behavior.
> > > 
> > > I totally agree.  Distros are changing into two different groups these
> > > days:
> > > 	- everything tied together and intregrated nicely for a specific
> > > 	  kernel version, userspace tool versions, etc.
> > > 	- flexible and works with multiple kernel versions, different
> > > 	  userspace tools, etc.
> > > 
> > > Distros in the first category are the "enterprise" releases (RHEL, SLES,
> > > etc.), as well as some consumer oriented distros (SuSE, Ubuntu, Fedora
> > > possibly.)
> > > 
> > > More flexible distros that handle different kernel versions are Gentoo,
> > > Debian, and probably Fedora.
> > > 
> > > And this is a natural progression as people try to provide a more
> > > complete "solution" for users.
> > > 
> > > When people to complain that they can't run a "kernel-of-the-day" on
> > > their "enterprise" distro, they are not realizing that that distro was
> > > just not developed to support that kind of thing at all.
> > 
> > I have to disagree somewhat violently to that statement, I'm afraid :-)
> > At least for me, it's pretty much a requirement that I can put eg
> > 2.6.18-rc2 on an enterprise install. It's a must to debug problems -
> > both ways, actually, testing both a new rc kernel on that enterprise
> > distro but also putting a vanilla kernel on the enterprise distro to
> > test something that fails with the distro kernel.
> 
> I agree that is is a _good_ thing that us kernel developers can do this,
> and that it isn't impossible (I do the same thing.)  But we also aren't
> worrying about the fact that our sound stopped working, or that the
> desktop icons don't show up anymore if we plug in a new device.  We are
> a very special case.

Definitely, when I built such a kernel I usually don't include sound or
usb :-)

> For any "user", they should not ever count on using a different kernel
> than what was shipped with the system (or updates) for an "enterprise"
> distro.  There are just too many little things that easily go wrong.

Sure, they move outside the supported zone very quickly if they do that.
But that's a different thing from the system actually not booting /
working with a vanilla kernel.

> > I'd absolutely hate if we got into a situation where you couldn't just
> > put a new vanilla kernel on SLESx. Calling it a complete solution to
> > just sounds like an excuse for breaking things that we don't have to.
> > Please lets not make things so fragile!
> 
> We are trying, but as everyone is so quick to point out, we (myself
> included) mess up at times :)

Mistakes happen for everybody, I think it's the intentional breakage
that people are yelling about :-)

-- 
Jens Axboe