Re: 2.6.20 instability

[Manuel L. <ma...@ro...>]

On Fri, Feb 02, 2007 at 04:45:56PM +0900, Paul Mundt wrote:
> On Fri, Feb 02, 2007 at 08:31:26AM +0100, Manuel Lauss wrote:
> > On Tue, Jan 30, 2007 at 09:36:38AM +0100, Manuel Lauss wrote:
> > > > My hesitation with this so far has been that some folks in the office
> > > > have hit troubles booting from CF with that applied, which I didn't see
> > > > on SATA when I was debugging it initially. I would prefer not to break
> > > > one set of boards in exchange for another, though it looks like it's
> > 
> > I see now what you mean: kernel occasionally oopses when I
> > insert a PCMCIA card, like this one:
> > 
> How is the situation if you have both
> 
>     sh: Don't set reserved _PAGE_WT bit on SH-3.
> 
> and
> 
>     sh: Lazy dcache writeback optimizations.
> 
> reverted? (git show <hash> | patch -p1 -R in that order works fine)

I don't run -git kernels so patch 1 is not applied anyway and
without patch 2 the situation is much worse: 
Kernel oopses every time a pcmcia ethernet card is inserted
(cf cards are not affected or much less frequently).
The difference is that for the ethernet card io ports are allocated
starting from 0x300, while the cf card io ports start at 0x0.
Also, the oops does not occur if the ethernet card is already in the
socket when kernel boots. I can then also reapeatedly eject/insert
it without problems.

> We're still not quite all the way there with the kmap_coherent() stuff
> (and the move to copy_user_highpage()), so that's still going to take a
> bit of work. While I think most of the page colouring problems are now
> taken care of, it seems in the PG_dcache_dirty route we're _still_
> missing some flushing that seems to break in certain paths regardless of
> the kmap state.

I guess I should study the mm code more closely to understand all that :)

> If you have issues with those two reverted, it would be interesting to
> see the logs. My SH7760 test board is much more stable with PG_mapped, at
> the cost of some performance.

What logs do you need?

Thanks,

-- 
  ml.