Bug 8748

Summary: bus hidden behind bridge / i965GM
Product: Drivers Reporter: Peter Ganzhorn (peter.ganzhorn)
Component: PCIAssignee: Bernhard Kaindl (bk)
Status: RESOLVED DUPLICATE    
Severity: normal CC: bunk, greg
Priority: P1    
Hardware: All   
OS: Linux   
Kernel Version: 2.6.22 Subsystem:
Regression: --- Bisected commit-id:

Description Peter Ganzhorn 2007-07-13 11:37:52 UTC
Most recent kernel where this bug did not occur: -
Distribution: Debian Lenny/Sid x86-64
Hardware Environment: Toshiba Tecra A9 (Core2Duo on i965GM)
Software Environment: 
Problem Description: My kernel complains about a bus hidden behind a bridge on my Intel ICH8 / i965GM based laptop:

PCI: Bus #06 (-#09) is hidden behind transparent bridge #05 (-#06) (try 'pci=assign-busses')
Please report the result to linux-kernel to fix this permanently

I guess I reported it now, so you can hopefully fix this, whatever the problem exactly is.
BTW: I did not experience any serious problems, I just saw the line in dmesg and decided that it's a nice day to do what it says and file a bug report :P

Here some more output from dmesg, maybe it's useful:

sor Core ID: 1
CPU1: Thermal monitoring enabled (TM2)
Intel(R) Core(TM)2 Duo CPU     T7300  @ 2.00GHz stepping 0a
checking TSC synchronization [CPU#0 -> CPU#1]: passed.
Brought up 2 CPUs
migration_cost=13
NET: Registered protocol family 16
ACPI: bus type pci registered
PCI: BIOS Bug: MCFG area at f0000000 is not E820-reserved
PCI: Not using MMCONFIG.
PCI: Using configuration type 1
ACPI: Interpreter enabled
ACPI: Using IOAPIC for interrupt routing
ACPI: PCI Root Bridge [PCI0] (0000:00)
PCI: Probing PCI hardware (bus 00)
PCI: Transparent bridge - 0000:00:1e.0
PCI: Bus #06 (-#09) is hidden behind transparent bridge #05 (-#06) (try 'pci=assign-busses')
Please report the result to linux-kernel to fix this permanently

And a lspci, just in case (if you need -vvv or so of specific devices tell me):

00:00.0 Host bridge: Intel Corporation Mobile Memory Controller Hub (rev 03)
00:02.0 VGA compatible controller: Intel Corporation Mobile Integrated Graphics Controller (rev 03)
00:02.1 Display controller: Intel Corporation Mobile Integrated Graphics Controller (rev 03)
00:19.0 Ethernet controller: Intel Corporation 82566MC Gigabit Network Connection (rev 03)
00:1a.0 USB Controller: Intel Corporation 82801H (ICH8 Family) USB UHCI #4 (rev 03)
00:1a.1 USB Controller: Intel Corporation 82801H (ICH8 Family) USB UHCI #5 (rev 03)
00:1a.7 USB Controller: Intel Corporation 82801H (ICH8 Family) USB2 EHCI #2 (rev 03)
00:1b.0 Audio device: Intel Corporation 82801H (ICH8 Family) HD Audio Controller (rev 03)
00:1c.0 PCI bridge: Intel Corporation 82801H (ICH8 Family) PCI Express Port 1 (rev 03)
00:1c.1 PCI bridge: Intel Corporation 82801H (ICH8 Family) PCI Express Port 2 (rev 03)
00:1c.2 PCI bridge: Intel Corporation 82801H (ICH8 Family) PCI Express Port 3 (rev 03)
00:1d.0 USB Controller: Intel Corporation 82801H (ICH8 Family) USB UHCI #1 (rev 03)
00:1d.1 USB Controller: Intel Corporation 82801H (ICH8 Family) USB UHCI #2 (rev 03)
00:1d.2 USB Controller: Intel Corporation 82801H (ICH8 Family) USB UHCI #3 (rev 03)
00:1d.7 USB Controller: Intel Corporation 82801H (ICH8 Family) USB2 EHCI #1 (rev 03)
00:1e.0 PCI bridge: Intel Corporation 82801 Mobile PCI Bridge (rev f3)
00:1f.0 ISA bridge: Intel Corporation Mobile LPC Interface Controller (rev 03)
00:1f.2 IDE interface: Intel Corporation Mobile SATA IDE Controller (rev 03)
01:00.0 Network controller: Intel Corporation Unknown device 4229 (rev 61)
05:0b.0 CardBus bridge: Texas Instruments PCIxx12 Cardbus Controller
05:0b.2 Mass storage controller: Texas Instruments 5-in-1 Multimedia Card Reader (SD/MMC/MS/MS PRO/xD)
05:0b.3 Generic system peripheral [0805]: Texas Instruments PCIxx12 SDA Standard Compliant SD Host Controller


Peter
Comment 1 Bernhard Kaindl 2007-10-16 06:35:22 UTC
Peter, thanks for the report.

It was a warning which I left in to be sure that the reason for it is properly dealt with, but we removed it from the normal user's sight now because we found

* that the PCI misconfiguration which is being indicated in this message only
  seems to be an issue with CardBus and
* that the CardBus fixup code which we have in place since 2.6.18 with appears
  to be sufficient.

Thus, I submitted a patch which was merged mainline with 2.6.22.6 and 2.6.23
that turns it into a message which is only enabled when debugging PCI, so in
practical users terms, the warning is gone.

*** This bug has been marked as a duplicate of bug 7531 ***