linux-kernel - Re: [PATCH] x86/pci: do assign root bus res if

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Message-Id: <200904291708.52830.bjorn.helgaas@hp.com>
Date:	Wed, 29 Apr 2009 17:08:51 -0600
From:	Bjorn Helgaas <bjorn.helgaas@...com>
To:	Yinghai Lu <yhlu.kernel@...il.com>
Cc:	Jesse Barnes <jbarnes@...tuousgeek.org>,
	Ingo Molnar <mingo@...e.hu>, "H. Peter Anvin" <hpa@...or.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	linux-pci@...r.kernel.org, Gary Hade <garyhade@...ibm.com>,
	Alex Chiang <achiang@...com>, linux-acpi@...r.kernel.org,
	Matthew Wilcox <matthew@....cx>
Subject: Re: [PATCH] x86/pci: do assign root bus res if _CRS is used

On Monday 27 April 2009 08:07:01 pm Yinghai Lu wrote:
> On Mon, Apr 27, 2009 at 3:24 PM, Bjorn Helgaas <bjorn.helgaas@...com> wrote:
> > On Monday 27 April 2009 03:00:16 pm Yinghai Lu wrote:
> >> On Mon, Apr 27, 2009 at 1:39 PM, Bjorn Helgaas <bjorn.helgaas@...com> wrote:
> >> >> other system may have broken _CRS.
> >> >
> >> > Do you have examples of problems here, or are you just worried that
> >> > there *may* be problems?
> >> one system with three chains... with pci=use_crs
> >> [    9.365669] pci_bus 0000:00: resource 0 io:  [0x00-0x3af]
> >> [    9.371065] pci_bus 0000:00: resource 1 io:  [0x3e0-0xcf7]
> >> [    9.376551] pci_bus 0000:00: resource 2 io:  [0x3b0-0x3bb]
> >> [    9.382028] pci_bus 0000:00: resource 3 io:  [0x3c0-0x3df]
> >> [    9.387513] pci_bus 0000:00: resource 4 io:  [0xd00-0xefff]
> >> [    9.393077] pci_bus 0000:00: resource 5 mem: [0x0a0000-0x0bffff]
> >> [    9.399084] pci_bus 0000:00: resource 6 mem: [0x0d0000-0x0dffff]
> >> [    9.405089] pci_bus 0000:00: resource 7 mem: [0xdd000000-0xdfffffff]
> >> [    9.505332] pci_bus 0000:40: resource 0 io:  [0x5000-0x8fff]
> >> [    9.510991] pci_bus 0000:40: resource 1 mem: [0xdb000000-0xdcffffff]
> >> [    9.553378] pci_bus 0000:80: resource 0 io:  [0x1000-0x4fff]
> >> [    9.559036] pci_bus 0000:80: resource 1 mem: [0xda000000-0xdaffffff]
> >>
> >> without that: amd_bus.c will read that from pci conf space
> >> [    9.310965] pci_bus 0000:00: resource 0 io:  [0x9000-0xefff]
> >> [    9.316621] pci_bus 0000:00: resource 1 io:  [0x00-0xfff]
> >> [    9.322020] pci_bus 0000:00: resource 2 mem: [0xdd000000-0xdfffffff]
> >> [    9.328373] pci_bus 0000:00: resource 3 mem: [0x0a0000-0x0bffff]
> >> [    9.334378] pci_bus 0000:00: resource 4 mem: [0xc0000000-0xd9ffffff]
> >> [    9.340731] pci_bus 0000:00: resource 5 mem: [0xf0000000-0xffffffff]
> >> [    9.347084] pci_bus 0000:00: resource 6 mem: [0x840000000-0xfcffffffff]
> >> [    9.444440] pci_bus 0000:40: resource 0 io:  [0x5000-0x8fff]
> >> [    9.450099] pci_bus 0000:40: resource 1 io:  [0xf000-0xffff]
> >> [    9.455757] pci_bus 0000:40: resource 2 mem: [0xdb000000-0xdcffffff]
> >> [    9.498118] pci_bus 0000:80: resource 0 io:  [0x1000-0x4fff]
> >> [    9.503777] pci_bus 0000:80: resource 1 mem: [0xda000000-0xdaffffff]
> >
> > It's interesting that many of the differences involve the legacy
> > VGA I/O ports in the 0x3b0-0x3df range.  My guess is that the AMD
> > chipset has special routing for those ranges.  If it didn't, it
> > would be difficult to support VGA devices under the other two
> > root bridges.  Maybe that VGA routing doesn't show up in the
> > bridge's PCI config space.  Can you tell from the ASL whether the
> > root bridge _SRS/_PRS/_CRS methods handle the VGA ranges specially?
> >
> > One of the differences is that PCI config space shows a 64-bit region
> > (bus 0000:00 mem 0x840000000-0xfcffffffff) that doesn't show up in
> > the _CRS info.  But the _CRS parsing depends on acpi_resource_to_address64(),
> > which doesn't know about the ACPI_RESOURCE_TYPE_EXTENDED_ADDRESS64
> > descriptors added in ACPI 3.0.  So this difference could be a result
> > of that Linux bug.  It'd be interesting to see whether the test patch
> > below makes a difference.
> will check it.

Did you learn anything about this?  I have a PNPACPI patch to parse
these new descriptors, but I don't have any machines where I can test
it.  If your box uses that descriptor, it'd be nice to test the patch
there.

> > The PCI config space region 0xf0000000-0xffffffff, also on bus 0000:00,
> > looks suspicious to me.  I thought that area contained a bunch of
> > BIOS-y things like reset vectors and local APICs.
> 
> in the amd_bus.c, will put left over resource to def HT chain.
> 
> YH
> 


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