Messages in this thread | | | From | (Linus Torvalds) | Subject | Re: simple pnp bios io resources bug makes system unusable | Date | 2 Jul 2003 17:20:21 GMT |
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In article <20030701223050.GA19402@neo.rr.com>, Adam Belay <ambx1@neo.rr.com> wrote: > >The pnpbios is reserving the complete range of every possible >io port. This causes device activation to fail for every device >that needs an io port because that resource will always appear >busy.
No, I don't think that's what it is doing at all. Quite the reverse, in fact.
Look:
>On Mon, Jun 30, 2003 at 11:38:17PM -0400, CarlosRomero wrote: >> >> cat /sys/devices/pnp0/00\:0c/resources >> io 0x00000000-0xffffffff
This means that "io" was zero, but more importantly, it means that "len" was zero too.
>> fixup: check for null io base, other devices are now able to initialize. > >Unfortunatly it's not quite that simple.
It _is_ that simple, but the code should check for "len" being zero, ie the fix looks like it should be just a simple
if (!len) return;
and that should fix it.
>Below are two examples that both use a base of 0 in a valid way.
Yes, and clearly they don't have "len == 0".
>Currently I'm leaning toward this logic... >if we have any of the following situations >- 0x00000000 for base and 0xffffffff for end >- 0x00000000 for base and 0x00000000 for end >- 0xffffffff for base and 0xffffffff for end >then the resource range can be considered disabled.
I would suggest:
- "len == 0" => obviously disabled (both IO and memory) - "end < base" => obviously disabled due to overflow crap - "end >= 0x10003" => IO disabled (yeah, non-x86 can have IO above that range in PCI, but I think it's undefined behaviour)
all three should be cases of "obviously we can't validly have such a resource", and the "len == 0" case should trivially fix the case that CarlosRomero saw.
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