I was unable to find a good description of the ServerWorks CNB20LE
chipset. However, it was probably exclusively used with the Pentium III
processor (this CPU model was used in all references to it that I
found where the CPU model was provided: dmesgs in [1] and [2];
[3] page 2; [4]-[7]).
As is widely known, the Pentium III processor did not support the 64-bit
mode, support for which was introduced by Intel a couple of years later.
So it is safe to assume that no systems with the CNB20LE chipset have
amd64 and the CONFIG_PCI_CNB20LE_QUIRK may now depend on X86_32.
Additionally, I have determined that most computers with the CNB20LE
chipset did have ACPI support and this driver was inactive on them.
I have submitted a patch to remove this driver, but it was met with
resistance [8].
[1] Jim Studt, Re: Problem with ServerWorks CNB20LE and lost interrupts
Linux Kernel Mailing List, https://lkml.org/lkml/2002/1/11/111
[2] RedHat Bug 665109 - e100 problems on old Compaq Proliant DL320
https://bugzilla.redhat.com/show_bug.cgi?id=665109
[3] R. Hughes-Jones, S. Dallison, G. Fairey, Performance Measurements on
Gigabit Ethernet NICs and Server Quality Motherboards,
http://datatag.web.cern.ch/papers/pfldnet2003-rhj.doc
[4] "Hardware for Linux",
Probe #d6b5151873 of Intel STL2-bd A28808-302 Desktop Computer (STL2)
https://linux-hardware.org/?probe=d6b5151873
[5] "Hardware for Linux", Probe #0b5d843f10 of Compaq ProLiant DL380
https://linux-hardware.org/?probe=0b5d843f10
[6] Ubuntu Forums, Dell Poweredge 2400 - Adaptec SCSI Bus AIC-7880
https://ubuntuforums.org/showthread.php?t=1689552
[7] Ira W. Snyder, "BISECTED: 2.6.35 (and -git) fail to boot: APIC problems"
https://lkml.org/lkml/2010/8/13/220
[8] Bjorn Helgaas, "Re: [PATCH] x86/pci: drop ServerWorks / Broadcom
CNB20LE PCI host bridge driver"
https://lore.kernel.org/lkml/20220318165535.GA840063@bhelgaas/T/
Signed-off-by: Mateusz Jończyk <mat.jonczyk@o2.pl>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: x86@kernel.org
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ira W. Snyder <ira.snyder@gmail.com>
Cc: Bjorn Helgaas <helgaas@kernel.org>
---
v2: make CONFIG_PCI_CNB20LE_QUIRK depend on X86_32
(previously only help text and description were changed)
upgrade short description.
arch/x86/Kconfig | 12 ++++++++++--
1 file changed, 10 insertions(+), 2 deletions(-)
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index fdfe8b7e895a..31f778b0cd0b 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -2739,13 +2739,21 @@ config MMCONF_FAM10H
depends on X86_64 && PCI_MMCONFIG && ACPI
config PCI_CNB20LE_QUIRK
- bool "Read CNB20LE Host Bridge Windows" if EXPERT
- depends on PCI
+ bool "Read PCI host bridge windows from the CNB20LE chipset" if EXPERT
+ depends on X86_32 && PCI
help
Read the PCI windows out of the CNB20LE host bridge. This allows
PCI hotplug to work on systems with the CNB20LE chipset which do
not have ACPI.
+ The ServerWorks (later Broadcom) CNB20LE was a chipset designed
+ most probably only for Pentium III.
+
+ To find out if you have such a chipset, search for a PCI device with
+ 1166:0009 PCI IDs, for example by executing
+ lspci -nn | grep '1166:0009'
+ The code is inactive if there is none.
+
There's no public spec for this chipset, and this functionality
is known to be incomplete.
--
2.25.1