Re: [PATCH] Remove Barcelona Thermal Throttling

["Russell Leidich" <rml@google.com>]

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All,

Sorry this took so long.  I have attached the Kconfig changes
requested by Andi, appended to the original patch.

On Feb 4, 2008 11:22 AM, Russell Leidich <rml@google.com> wrote:
> On Feb 3, 2008 11:20 PM, Andi Kleen <andi@firstfloor.org> wrote:
> > On Sun, Feb 03, 2008 at 10:13:53PM -0800, Russell Leidich wrote:
> > > All,
> > >
> > > You can imagine my dismay when I recently learned that, after all our
> > > collective effort, hardware thermal throttling does not work reliably
> > > on Barcelona, according to AMD.  Due to NDA restrictions, I am unable
> > > to provide further details.
> >
> > Too bad. Hopefully that code will work then on the hypothetic
> > future parts with fixed throttling. Perhaps it would be better
> > to just remove it now and readd later.
>
> I really think it's best to leave it in.  It's harmless at the moment,
> and readding it later will just create a massive amount of duplicate
> work.    Sooner or later, I'm have little doubt that AMD can make this
> feature work.
>
> >
> > All this reminds me you need to adjust the Kconfig dependencies
> > for K8_NB too to be always enabled with MCE_AMD.
> >
> > Ideally on top of this patch with a || MCE_AMD
>
> OK, if you'll take the patch, I'd be happy to do this :).  I'm
> assuming that you mean I should force K8_NB = "yes" if MCE_AMD = "yes"
> in .config.  Is that what you're asking for?
>
> >
> > -Andi

-- 
Russell Leidich

[-- Attachment #2: patch.txt --]
[-- Type: text/plain, Size: 3048 bytes --]

Signed-off-by: Russell Leidich <rml@google.com>
--- linux-2.6.24-rc5.orig/arch/x86/kernel/cpu/mcheck/mce_amd_64.c	2008-02-03 21:17:58.186613000 -0800
+++ linux-2.6.24-rc5/arch/x86/kernel/cpu/mcheck/mce_amd_64.c	2008-02-03 21:51:38.810989000 -0800
@@ -742,13 +742,20 @@ static void smp_thermal_northbridge_init
 		 */
 		pci_read_config_dword(k8_northbridges[nb_num],
 					THERM_CTL_F3X64, &therm_ctl_f3x64);
-		therm_ctl_f3x64 |= PSL_APIC_HI_EN | HTC_EN;
+		therm_ctl_f3x64 |= PSL_APIC_HI_EN;
 		therm_ctl_f3x64 &= (~PSL_APIC_LO_EN);
 		pci_write_config_dword(k8_northbridges[nb_num],
 					THERM_CTL_F3X64, therm_ctl_f3x64);
-		printk(KERN_INFO "CPU thermal throttling interrupts enabled in "
-			"PCI bus 0x0, device 0x%x, function 0x3, register 0x64."
-			"\n", k8_northbridges[nb_num]->devfn >> 3);
+		if (therm_ctl_f3x64 & HTC_EN)
+			printk(KERN_INFO "CPU thermal throttling interrupts "
+				"enabled in PCI bus 0x0, device 0x%x, function "
+				"0x3, register 0x64.\n",
+				PCI_SLOT(k8_northbridges[nb_num]->devfn));
+		else
+			printk(KERN_WARNING "CPU thermal throttling disabled by"
+				" the BIOS in PCI bus 0x0, device 0x%x, "
+				"function 0x3, register 0x64, bit 0x0.\n",
+				PCI_SLOT(k8_northbridges[nb_num]->devfn));
 	}
 }
 
@@ -835,7 +842,7 @@ static void smp_thermal_early_throttle_c
  * corresponding APIC initialization on each core.
  *
  * Due to an erratum involving the thermal sensor, this code does not work on
- * any CPU prior to Family 0x10.
+ * CPUs with certain northbridge device IDs, as coded below.
  */
 static int smp_thermal_interrupt_init(void)
 {
@@ -844,13 +851,15 @@ static int smp_thermal_interrupt_init(vo
 	if (num_k8_northbridges == 0)
 		goto out;
 	/*
-	 * If any of the northbridges has PCI ID 0x1103, then its thermal
-	 * hardware suffers from an erratum which prevents this code from
-	 * working, so abort.  (This implies that it only works on Family
-	 * 0x10.)
+	 * If any of the northbridges has any of the device IDs in the following
+	 * loop, then the hardware suffers from an erratum which prevents
+	 * this code from working, so abort.
 	 */
 	for (nb_num = 0; nb_num < num_k8_northbridges; nb_num++) {
-		if ((k8_northbridges[nb_num]->device) == 0x1103)
+		__u32 device_id;
+
+		device_id = k8_northbridges[nb_num]->device;
+		if ((device_id == 0x1103) || (device_id == 0x1203))
 			goto out;
 	}
 	/*
--- linux-2.6.24-rc5.orig/arch/x86/Kconfig	2007-12-11 14:30:52.708983000 -0800
+++ linux-2.6.24-rc5/arch/x86/Kconfig	2008-02-12 11:01:24.860123000 -0800
@@ -564,6 +564,7 @@ config X86_MCE_INTEL
 config X86_MCE_AMD
 	bool "AMD MCE features"
 	depends on X86_64 && X86_MCE && X86_LOCAL_APIC
+	select K8_NB
 	default y
 	help
 	   Additional support for AMD specific MCE features such as
@@ -1559,8 +1560,7 @@ endif # X86_32
 
 config K8_NB
 	def_bool y
-	depends on AGP_AMD64 || (X86_64 && (GART_IOMMU || (PCI && NUMA)))
-
+	depends on AGP_AMD64 || (X86_64 && (GART_IOMMU || (PCI && NUMA))) || X86_MCE_AMD
 source "drivers/pcmcia/Kconfig"
 
 source "drivers/pci/hotplug/Kconfig"