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

From: Yinghai Lu
Date: Fri May 02 2008 - 05:19:44 EST


On Fri, May 2, 2008 at 12:44 AM, Ingo Molnar <mingo@xxxxxxx> wrote:
>
> * Matt Domsch <Matt_Domsch@xxxxxxxx> 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?
>

please check the patch in x86.git, it should do the same thing, but
put the call in pci_access_init...

commit 9817aa147000086bc11b571620ecc1c73a4a614b
Author: Yinghai Lu <yhlu.kernel@xxxxxxxxx>
Date: Mon Apr 14 15:40:37 2008 -0700

x86 PCI: call dmi_check_pciprobe()

this change:

| commit 08f1c192c3c32797068bfe97738babb3295bbf42
| Author: Muli Ben-Yehuda <muli@xxxxxxxxxx>
| Date: Sun Jul 22 00:23:39 2007 +0300
|
| x86-64: introduce struct pci_sysdata to facilitate sharing of ->sysdata
|
| This patch introduces struct pci_sysdata to x86 and x86-64, and
| converts the existing two users (NUMA, Calgary) to use it.
|
| This lays the groundwork for having other users of sysdata, such as
| the PCI domains work.
|
| The Calgary bits are tested, the NUMA bits just look ok.

replaces pcibios_scan_root with pci_scan_bus_parented...

but in pcibios_scan_root we have a DMI check:

dmi_check_system(pciprobe_dmi_table);

when when have several peer root buses this could be called multiple
times (which is bad), so move that call to pci_access_init().

Signed-off-by: Yinghai Lu <yhlu.kernel@xxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxx>
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
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