Re: [PATCH] fix x86 DMI checks for PCI quirks

[Ingo Molnar <mingo@elte.hu>]

* Matt Domsch <Matt_Domsch@dell.com> wrote:

> fix x86 DMI checks for PCI quirks
> 
> http://bugzilla.kernel.org/show_bug.cgi?id=10583
> https://bugzilla.redhat.com/show_bug.cgi?id=444791
> 
> Since git commit 08f1c192c3c32797068bfe97738babb3295bbf42 (between 
> kernels 2.6.22 and 2.6.23), arch/x86/pci/acpi.c has not called 
> pcibios_scan_root(), which would have called 
> arch/x86/pci/common.c:dmi_check_system().  This has prevented the 
> quirks listed in pciprobe_dmi_table[] from being checked and 
> appropriate action taken.

ugh ...

> This manifests itself in several Dell and HP servers not automatically 
> having the pci=bfsort option be applied, as well as Samsung X20 and 
> Compaq EVO N800c systems needing pci=assign-all-busses was no longer 
> automatically applied.
> 
> This patch moves the DMI tests into its own file, arch/x86/pci/dmi.c, 
> and invokes them via subsys_initcall() before pci_acpi_init(), 
> pci_legacy_init(), and pcibios_init() are called, which may rely upon 
> these tests having been executed.

Jesse Barnes (new PCI maintainer) Cc:-ed.

i'm wondering how we could avoid such mishaps in the future. This was 
broken from 2.6.23 through 2.6.25 - way too long. Perhaps we should 
create a known signature of the device tree in user-space, and somehow 
warn if the kernel changes it? Could this somehow be put into the 
kernel?

	Ingo