Re: 2.6.13.1 locks machine after some time, 2.6.12.5 work fine

From: Linus Torvalds
Date: Tue Sep 13 2005 - 12:24:36 EST




On Tue, 13 Sep 2005, Norbert Kiesel wrote:
>
> Ok, I applied the patch and I'm running it right now, so far so good.
> Here is the the output of lspci from the patched 2.6.13.1 (not sure if a
> diff to the unpatched 2.6.13.1 or the 2.6.12.5 would be more useful, so
> I settled for no diff :-).

Yes, now it looks better, except for a lspci quirk. You have:

> 0000:00:10.0 RAID bus controller: Silicon Image, Inc. SiI 0649
> Ultra ATA/100 PCI to ATA Host Controller (rev 01)

and lspci reports:

> Expansion ROM at 40000000 [disabled] [size=512K]

where the "disabled" comes from the fact that it looks at the sysfs data
structures, and the resource is indeed marked as disabled there (because
nothing enabled it explicitly).

But then reading the HW registers, we see:

> 30: 01 00 00 40 60 00 00 00 00 00 00 00 0c 01 02 04

Ie now the ROM address value is 0x40000001, which means that as far as the
_hardware_ is concerned, the ROM is actually enabled.

That's because the cmd64x driver enabled the ROM by just writing the
enable bit directly, and never actually told the resource layer that it
had done so. Not a big deal - we've properly allocated the resource
region, so there's no overlap, there's just this strange disconnect
between what the hardware thinks and what the resource handling things.

Anyway, it all looks reasonable. Of course, exactly like with the hpt
driver, there doesn't seem to be any real _reason_ to enable the ROM in
the first place, and that code is #ifdef __i386__ anyway (so if there
_was_ a reason, it wouldn't work on anything else than an x86), so I
suspect we should just remove the ROM enable entirely.

But it really shouldn't matter - at least we now enable the ROM
_correctly_, and I'm pretty sure (and certainly sincerely hope ;) that
your lockup is gone.

Linus
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