From 704c528bee45fc37546542bf578181cec0845a67 Mon Sep 17 00:00:00 2001
From: Tejun Heo <tj@kernel.org>
Date: Mon, 26 Oct 2009 15:41:46 +0100
Subject: [PATCH] x86: Fix iommu=nodac parameter handling
commit 2ae8bb75db1f3de422eb5898f2a063c46c36dba8 upstream.
iommu=nodac should forbid dac instead of enabling it. Fix it.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: Matteo Frigo <athena@fftw.org>
LKML-Reference: <4AE5B52A.4050408@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---
arch/x86/kernel/pci-dma.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/x86/kernel/pci-dma.c b/arch/x86/kernel/pci-dma.c
index a6e804d16c35..6ac3931160d7 100644
--- a/arch/x86/kernel/pci-dma.c
+++ b/arch/x86/kernel/pci-dma.c
@@ -214,7 +214,7 @@ static __init int iommu_setup(char *p)
if (!strncmp(p, "allowdac", 8))
forbid_dac = 0;
if (!strncmp(p, "nodac", 5))
- forbid_dac = -1;
+ forbid_dac = 1;
if (!strncmp(p, "usedac", 6)) {
forbid_dac = -1;
return 1;
--
2.34.1