Re: [rfc] hw resource debugging checks

[Arjan van de Ven]

On Sun, 13 Apr 2008 22:01:23 -0700
"Yinghai Lu" <yhlu.kernel@xxxxxxxxx> wrote:

> On Sun, Apr 13, 2008 at 8:52 PM, Arjan van de Ven
> <arjan@xxxxxxxxxxxxx> wrote:
> >
> > On Sun, 13 Apr 2008 12:29:30 -0700
> >  "Yinghai Lu" <yhlu.kernel@xxxxxxxxx> wrote:
> >
> >  > On Sun, Apr 13, 2008 at 11:29 AM, Andi Kleen
> >  > <andi@xxxxxxxxxxxxxx> wrote:
> >  > > > even I could talk to BIOS
> >  > >  > engineers everyday and tell them how to fix the problem in
> >  > >  > BIOS,  some still can not be fixed because of the legacy
> >  > >  > BIOS framework or big mess.
> >  > >
> >  > >  ... so you opt to create the big mess in the kernel. Great.
> >  > >
> >  > >  And it does not even fixes a real problem, but getting
> >  > >  mmconfig or the numa bus discovery to work is not really a too
> >  > > serious issue anyways. At best it is the icing on the cake to
> >  > > enable some relatively obscure functionality and be a little
> >  > > more efficient, but nothing really fundamental.
> >  > >
> >  > >  But for those things just expecting a working modern BIOS is
> >  > > quite reasonable.
> >  >
> >  > it does fix real problem. when big system with several HT links,
> >  > and every link some pcie slots.
> >  > you fully load pci-e cards (with pci bridge). BIOS will stop
> >  > assign io/mmio resource to left device if it run out of io port
> >  > range. (though it is supposed to go on to allocate mmio to left
> >  > devices) ( modern pcie device only need mmio with drivers)
> >  >
> >  > With pre set range allocation in NB pci conf, kernel could
> >  > allocate the resource in every peer root bus ranges.
> >  > (the code for assign resource to device that is not assigned
> >  > resource by BIOS --- already in kernel)
> >  >
> >
> >  there is a really big difference between assigning PCI device
> > resources and doing a whole thing like MMCFG from scratch.
> >
> that MCONF patchset for AMD fam10h include
> 1. get mmconfig from MSR, MCFG is using that too, if that is right,
> and we will get MCONF support when acpi support is off, and MCFG is
> broken.
> 2. or assign 0xfc00000000 to that MSR, that is safe too.

using MCONF when the ACPI support isn't there is just a deathtrap.
To be honest, if you want to break the AMD machines out there, who am
I to care about that, I work for Intel. But I'm worried someone thinks 
this can be done for Intel based systems too, and then carry over all
the bad bugs to those as well ;(



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