From 73472a46b5b28116b145fb5fc05242c1aa8e1461 Mon Sep 17 00:00:00 2001 From: "Pallipadi, Venkatesh" Date: Thu, 21 Jan 2010 11:09:52 -0800 Subject: x86: Disable HPET MSI on ATI SB700/SB800 HPET MSI on platforms with ATI SB700/SB800 as they seem to have some side-effects on floppy DMA. Do not use HPET MSI on such platforms. Original problem report from Mark Hounschell http://lkml.indiana.edu/hypermail/linux/kernel/0912.2/01118.html [ This patch needs to go to stable as well. But, there are some conflicts that prevents the patch from going as is. I can rebase/resubmit to stable once the patch goes upstream. hpa: still Cc:'ing stable@ as an FYI. ] Tested-by: Mark Hounschell Signed-off-by: Venkatesh Pallipadi Cc: LKML-Reference: <20100121190952.GA32523@linux-os.sc.intel.com> Signed-off-by: H. Peter Anvin --- arch/x86/kernel/hpet.c | 8 ++++++++ 1 file changed, 8 insertions(+) (limited to 'arch/x86/kernel/hpet.c') diff --git a/arch/x86/kernel/hpet.c b/arch/x86/kernel/hpet.c index ba6e65884603..ad80a1c718c6 100644 --- a/arch/x86/kernel/hpet.c +++ b/arch/x86/kernel/hpet.c @@ -34,6 +34,8 @@ */ unsigned long hpet_address; u8 hpet_blockid; /* OS timer block num */ +u8 hpet_msi_disable; + #ifdef CONFIG_PCI_MSI static unsigned long hpet_num_timers; #endif @@ -596,6 +598,9 @@ static void hpet_msi_capability_lookup(unsigned int start_timer) unsigned int num_timers_used = 0; int i; + if (hpet_msi_disable) + return; + if (boot_cpu_has(X86_FEATURE_ARAT)) return; id = hpet_readl(HPET_ID); @@ -928,6 +933,9 @@ static __init int hpet_late_init(void) hpet_reserve_platform_timers(hpet_readl(HPET_ID)); hpet_print_config(); + if (hpet_msi_disable) + return 0; + if (boot_cpu_has(X86_FEATURE_ARAT)) return 0; -- cgit v1.2.1