Re: [PATCH 1/1] Fix boot on efi 32 bit Machines [try #4]

[Chuck Ebbert]

In-Reply-To: <Pine.LNX.4.64.0607131507220.5623@xxxxxxxxxxx>

On Thu, 13 Jul 2006 15:15:21 -0700, Linus Torvalds wrote:

> > From kernel 2.6.16 to kernel 2.6.17 a new check is made.
> > File arch/i386/pci/mmconfig.c -> funktion pci_mmcfg_init -> check e820_all_mapped
> > The courios thing is that this check will always fail on the
> > Intel Macs booted through efi. Parsing of the ACPI_MCFG table
> > returns e0000000 for the start. But this location is
> > not in the memory map which the efi firmware have :
> > BIOS-EFI: 00000000e00f8000 - 00000000e00f9000 (reserved)
> 
> It _sounds_ like you may not have converted all the EFI types 
> (EFI_UNUSABLE_MEMORY?), but regardless, I think it would be fine to have 
> perhaps a "PCI_FORCE_MMCONF" flag that avoided that sanity check, and then 
> you could have some code (either the EFI code _or_ some DMI code) that 
> sets it for the Intel Macs.
> 
> Note that the check in pci_mmcfg_init() shouldn't be some EFI hack itself, 
> it would be a real flag for the PCI subsystem, independently of EFI (I can 
> see it being useful for a kernel command line option, even), and the only 
> EFI connection would be that perhaps the EFI code ends up setting that 
> flag (especially if there is some EFI command for doing this).
> 
> Btw, if you do do this, I think we should make sure that the MMCONFIG base 
> address is reserved in the PCI MMIO resource structures (which we don't do 
> now, I think - part of the whole point of verifying that it's marked as 
> E820_RESERVED is exactly the fact that otherwise we migth have problems 
> with PCI MMIO resource allocations allocating a regular PCI resource over 
> the MMCONFIG space..)

I just reposted Rajesh's patch for this (fixed the one previous complaint
from the list.)

 Subj:  [patch, take 3] PCI: use ACPI to verify extended config space on x86

Edgar, can you get it and test?

Discussion should probably continue in that thread...

-- 
Chuck
 "You can't read a newspaper if you can't read."  --George W. Bush
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