[PATCH 4.6 02/96] x86/quirks: Apply nvidia_bugs quirk only on root bus

From: Greg Kroah-Hartman
Date: Mon Aug 08 2016 - 15:40:08 EST


4.6-stable review patch. If anyone has any objections, please let me know.

------------------

From: Lukas Wunner <lukas@xxxxxxxxx>

commit 447d29d1d3aed839e74c2401ef63387780ac51ed upstream.

Since the following commit:

8659c406ade3 ("x86: only scan the root bus in early PCI quirks")

... early quirks are only applied to devices on the root bus.

The motivation was to prevent application of the nvidia_bugs quirk on
secondary buses.

We're about to reintroduce scanning of secondary buses for a quirk to
reset the Broadcom 4331 wireless card on 2011/2012 Macs. To prevent
regressions, open code the requirement to apply nvidia_bugs only on the
root bus.

Signed-off-by: Lukas Wunner <lukas@xxxxxxxxx>
Cc: Andy Lutomirski <luto@xxxxxxxxxx>
Cc: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: Brian Gerst <brgerst@xxxxxxxxx>
Cc: Denys Vlasenko <dvlasenk@xxxxxxxxxx>
Cc: H. Peter Anvin <hpa@xxxxxxxxx>
Cc: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Yinghai Lu <yinghai@xxxxxxxxxx>
Link: http://lkml.kernel.org/r/4d5477c1d76b2f0387a780f2142bbcdd9fee869b.1465690253.git.lukas@xxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
arch/x86/kernel/early-quirks.c | 7 +++++++
1 file changed, 7 insertions(+)

--- a/arch/x86/kernel/early-quirks.c
+++ b/arch/x86/kernel/early-quirks.c
@@ -76,6 +76,13 @@ static void __init nvidia_bugs(int num,
#ifdef CONFIG_ACPI
#ifdef CONFIG_X86_IO_APIC
/*
+ * Only applies to Nvidia root ports (bus 0) and not to
+ * Nvidia graphics cards with PCI ports on secondary buses.
+ */
+ if (num)
+ return;
+
+ /*
* All timer overrides on Nvidia are
* wrong unless HPET is enabled.
* Unfortunately that's not true on many Asus boards.