Patch "x86/Kconfig: Make CONFIG_PCI_CNB20LE_QUIRK depend on X86_32" has been added to the 6.14-stable tree

This is a note to let you know that I've just added the patch titled

x86/Kconfig: Make CONFIG_PCI_CNB20LE_QUIRK depend on X86_32

to the 6.14-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
x86-kconfig-make-config_pci_cnb20le_quirk-depend-on-.patch
and it can be found in the queue-6.14 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

commit 8cc03c8c367ced0228a5fbaec8c02274f11b2a38

Author: Mateusz Jończyk <[email protected]>
Date:   Fri Mar 21 21:48:48 2025 +0100

x86/Kconfig: Make CONFIG_PCI_CNB20LE_QUIRK depend on X86_32

[ Upstream commit d9f87802676bb23b9425aea8ad95c76ad9b50c6e ]

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 <[email protected]>

Signed-off-by David Heideberg <[email protected]>

Signed-off-by Ingo Molnar <[email protected]>

Cc "H. Peter Anvin" <[email protected]>

Cc Linus Torvalds <[email protected]>

Link https://lore.kernel.org/r/[email protected] open here

Signed-off-by Sasha Levin <[email protected]>

arch/x86/Kconfig +0 -0

index aeb95b6e55369..de47e7c435679 100644
@@ -2981,13 +2981,21 @@ config MMCONF_FAM10H
 	depends on X86_64 && PCI_MMCONFIG && ACPI
 

config PCI_CNB20LE_QUIRK

arch/x86/Kconfig +2 -2

-	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.

arch/x86/Kconfig +8 -0

+	  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.

Dnia 29 kwietnia 2025 03:41:48 CEST, Sasha Levin <[email protected]> napisał/a:

Quoted 11 lines

This is a note to let you know that I've just added the patch titled

x86/Kconfig: Make CONFIG_PCI_CNB20LE_QUIRK depend on X86_32

to the 6.14-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
x86-kconfig-make-config_pci_cnb20le_quirk-depend-on-.patch
and it can be found in the queue-6.14 subdirectory.

Quoted 2 lines

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

Hello,

I'd like to ask that this patch be dropped from the stable queues (for 6.14 and earlier kernels). It does not fix anything important, it is just for convenience - to
hide this one option from amd64 kernel Kconfig.