linux/arch/i386
Bernhard Kaindl 8c4b2cf9af [PATCH] PCI: PCI/Cardbus cards hidden, needs pci=assign-busses to fix
"In some cases, especially on modern laptops with a lot of PCI and cardbus
bridges, we're unable to assign correct secondary/subordinate bus numbers
to all cardbus bridges due to BIOS limitations unless we are using
"pci=assign-busses" boot option." -- Ivan Kokshaysky (from a patch comment)

Without it, Cardbus cards inserted are never seen by PCI because the parent
PCI-PCI Bridge of the Cardbus bridge will not pass and translate Type 1 PCI
configuration cycles correctly and the system will fail to find and
initialise the PCI devices in the system.

Reference: PCI-PCI Bridges: PCI Configuration Cycles and PCI Bus Numbering:
http://www.science.unitn.it/~fiorella/guidelinux/tlk/node72.html

The reason for this is that:
 ``All PCI busses located behind a PCI-PCI bridge must reside between the
secondary bus number and the subordinate bus number (inclusive).''

"pci=assign-busses" makes pcibios_assign_all_busses return 1 and this
turns on PCI renumbering during PCI probing.

Alan suggested to use DMI automatically set assign-busses on problem systems.

The only question for me was where to put it.  I put it directly before
scanning PCI bus into pcibios_scan_root() because it's called from legacy,
acpi and numa and so it can be one place for all systems and configurations
which may need it.

AMD64 Laptops are also affected and fixed by assign-busses, and the code is
also incuded from arch/x86_64/pci/ that place will also work for x86_64
kernels, I only ifdef'-ed the x86-only Laptop in this example.

Affected and known or assumed to be fixed with it are (found by googling):

* ASUS Z71V and L3s
* Samsung X20
* Compaq R3140us and all Compaq R3000 series laptops with TI1620 Controller,
  also Compaq R4000 series (from a kernel.org bugreport)
* HP zv5000z (AMD64 3700+, known that fixup_parent_subordinate_busnr fixes it)
* HP zv5200z
* IBM ThinkPad 240
* An IBM ThinkPad (1.8 GHz Pentium M) debugged by Pavel Machek
  gives the correspondig message which detects the possible problem.
* MSI S260 / Medion SIM 2100 MD 95600

The patch also expands the "try pci=assign-busses" warning so testers will
help us to update the DMI table.

Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Dominik Brodowski <linux@dominikbrodowski.net>
Cc: Russell King <rmk@arm.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2006-03-23 14:35:14 -08:00
..
boot [PATCH] x86: gitignore some autogenerated files for i386 2006-02-14 16:09:35 -08:00
crypto [CRYPTO] aes-i586: Remove unused variable ls_tab 2006-01-09 14:15:53 -08:00
kernel [PATCH] PCI: resource address mismatch 2006-03-23 14:35:14 -08:00
lib [LIB]: Consolidate _atomic_dec_and_lock() 2005-09-14 21:47:01 -07:00
mach-default [PATCH] Fix topology.c location 2006-02-24 14:31:39 -08:00
mach-es7000 [PATCH] Compilation fix for ES7000 when no ACPI is specified in config (i386) 2006-03-23 07:38:04 -08:00
mach-generic [PATCH] x86: sutomatically enable bigsmp when we have more than 8 CPUs 2005-09-05 00:06:10 -07:00
mach-visws [PATCH] useless includes of linux/irq.h in arch/i386 2005-09-26 18:29:50 -07:00
mach-voyager [PATCH] fix voyager after topology.c move 2006-02-26 19:10:30 -08:00
math-emu [PATCH] i386: inline assembler: cleanup and encapsulate descriptor and task register management 2005-09-05 00:06:11 -07:00
mm [PATCH] pause_on_oops command line option 2006-03-23 07:38:16 -08:00
oprofile [PATCH] more for_each_cpu() conversions 2006-03-23 07:38:17 -08:00
pci [PATCH] PCI: PCI/Cardbus cards hidden, needs pci=assign-busses to fix 2006-03-23 14:35:14 -08:00
power [PATCH] x86: add MCE resume 2005-11-07 07:53:30 -08:00
defconfig update the i386 defconfig 2006-03-20 20:14:06 +01:00
Kconfig [PATCH] x86: some fixups for the X86_NUMAQ dependencies 2006-03-23 07:38:06 -08:00
Kconfig.cpu [PATCH] Base support for AMD Geode GX/LX processors 2006-01-06 08:33:38 -08:00
Kconfig.debug [PATCH] i386: multi-column stack backtraces 2006-03-23 07:38:03 -08:00
Makefile [PATCH] i386: remove gcc version check for CONFIG_REGPARM 2006-01-16 23:15:25 -08:00
Makefile.cpu [PATCH] remove gcc-2 checks 2006-01-08 20:14:02 -08:00