linux-kernel - Re: [PATCH] x86: enable hpet=force for AMD SB400

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Date:	Sat, 10 May 2008 22:40:41 +0200 (CEST)
From:	Thomas Gleixner <tglx@...utronix.de>
To:	Andrew Morton <akpm@...ux-foundation.org>
cc:	andreas.herrmann3@....com, mingo@...e.hu, hpa@...or.com,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] x86: enable hpet=force for AMD SB400

On Fri, 9 May 2008, Andrew Morton wrote:
> On Sat, 10 May 2008 01:42:30 +0200 (CEST)
> Thomas Gleixner <tglx@...utronix.de> wrote:
> 
> > On Fri, 9 May 2008, Andrew Morton wrote:
> > > On Fri, 9 May 2008 11:49:11 +0200
> > > Andreas Herrmann <andreas.herrmann3@....com> wrote:
> > > 
> > > > x86: enable hpet=force for ATI SB400
> > > 
> > > Sigh.
> > > 
> > > > Add quirk to allow forced usage of HPET on ATI SB400.
> > > > I stumbled over machines where HPET is enabled but not reported
> > > > by BIOS.
> > > 
> > > Is there no way in which we can probe for or identify this condition,
> > > rather than hoping that the user will find out about this boot option?
> > 
> > I'd love to have a sane solution for that, but looking at the rate of
> > HPET wreckage since we increased the usage of HPET I'm happy to have
> > this as an opt in thingy.
> > 
> 
> Well we don't have to auto-enable the hpet.  Simply adding a loud "you
> should try the hpet=force option" printk would help a lot of people.

Something like this ? That's on top of linus + Andreas SB400 patch

Thanks,
	tglx

------------> 
commit 3d5f406b110b1b1d314805a1a4c1744ff05d7f22
Author: Thomas Gleixner <tglx@...utronix.de>
Date:   Sat May 10 21:42:14 2008 +0200

    x86: print info about available HPET quirk
    
    We have a lot of HPET quirks available which might force enable HPET
    even when the BIOS does not enable it. Some of those quirks depend on
    the command line option "hpet=force".
    
    Andrew pointed out that hoping that the user will find out about this
    boot option is not really helpful.
    
    Emit a kernel info which informs the user about the "hpet=force" boot
    option when we enter a quirk which depends on this option and the user
    did not provide it.
    
    Signed-off-by: Thomas Gleixner <tglx@...utronix.de>

diff --git a/arch/x86/kernel/quirks.c b/arch/x86/kernel/quirks.c
index 5fe6bd5..ddbf34d 100644
--- a/arch/x86/kernel/quirks.c
+++ b/arch/x86/kernel/quirks.c
@@ -175,6 +175,12 @@ DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_ICH9_7,
 
 static struct pci_dev *cached_dev;
 
+static void hpet_print_force_info(void)
+{
+	printk(KERN_INFO "HPET not enabled in BIOS. "
+	       "You might try hpet=force boot option\n");
+}
+
 static void old_ich_force_hpet_resume(void)
 {
 	u32 val;
@@ -254,6 +260,8 @@ static void old_ich_force_enable_hpet_user(struct pci_dev *dev)
 {
 	if (hpet_force_user)
 		old_ich_force_enable_hpet(dev);
+	else
+		hpet_print_force_info();
 }
 
 DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_82801CA_0,
@@ -291,8 +299,13 @@ static void vt8237_force_enable_hpet(struct pci_dev *dev)
 {
 	u32 uninitialized_var(val);
 
-	if (!hpet_force_user || hpet_address || force_hpet_address)
+	if (hpet_address || force_hpet_address)
+		return;
+
+	if (!hpet_force_user) {
+		hpet_print_force_info();
 		return;
+	}
 
 	pci_read_config_dword(dev, 0x68, &val);
 	/*
@@ -341,8 +354,13 @@ static void ati_force_enable_hpet(struct pci_dev *dev)
 {
 	u32 uninitialized_var(val);
 
-	if (!hpet_force_user || hpet_address || force_hpet_address)
+	if (hpet_address || force_hpet_address)
+		return;
+
+	if (!hpet_force_user) {
+		hpet_print_force_info();
 		return;
+	}
 
 	pci_write_config_dword(dev, 0x14, 0xfed00000);
 	pci_read_config_dword(dev, 0x14, &val);
@@ -369,8 +387,13 @@ static void nvidia_force_enable_hpet(struct pci_dev *dev)
 {
 	u32 uninitialized_var(val);
 
-	if (!hpet_force_user || hpet_address || force_hpet_address)
+	if (hpet_address || force_hpet_address)
+		return;
+
+	if (!hpet_force_user) {
+		hpet_print_force_info();
 		return;
+	}
 
 	pci_write_config_dword(dev, 0x44, 0xfed00001);
 	pci_read_config_dword(dev, 0x44, &val);
--
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