There are HP servers where the BIOS is capable of managing P-states
inherently. On those systems the BIOS does not provide the relevant ACPI
data (_PSS,_PCT etc.) to the OS. We don't want to print the following
"firmware bug" error messages on those servers:
[Firmware Bug]: powernow-k8: No compatible ACPI _PSS objects found.
[Firmware Bug]: powernow-k8: Try again with latest BIOS.
I think in each of the following cases the call to
acpi_processor_register_performance() will fail in the P-state driver:
1) a buggy BIOS (that relinquishes control to the P-state driver, but has
an error in the ACPI data)
2) a BIOS that doesn't intentionally expose relevant ACPI info because the
HW is buggy
3) a BIOS that manages P-states inherently and doesn't want to provide
the cpufreq-related ACPI data
There is no simple/clean way to distinguish between these cases.
Below is a whitelist that mentions those AMD-based HP x86 servers whose BIOS
have the capability of managing P-states. But whitelists are ugly ...
Comments?
- naga -
--------------------
On systems where the BIOS is capable of managing P-states, no relevant ACPI
info (_PCT,_PSS etc.) is provided to the driver/OS. Avoid printing the
"firmware bug" error messages in those cases.
Signed-off-by: Naga Chumbalkar <nagananda.chumbalkar@xxxxxx>
---
diff --git a/arch/x86/kernel/cpu/cpufreq/powernow-k8.c b/arch/x86/kernel/cpu/cpufreq/powernow-k8.c
index a9df944..5712478 100644
--- a/arch/x86/kernel/cpu/cpufreq/powernow-k8.c
+++ b/arch/x86/kernel/cpu/cpufreq/powernow-k8.c
@@ -36,6 +36,7 @@
#include <linux/sched.h> /* for current / set_cpus_allowed() */
#include <linux/io.h>
#include <linux/delay.h>
+#include <linux/dmi.h>
#include <asm/msr.h>
@@ -1239,12 +1240,88 @@ static void __cpuinit powernowk8_cpu_init_on_cpu(void *_init_on_cpu)
init_on_cpu->rc = 0;
}
+/*
+ * Some BIOSes may not present P-state related ACPI information
+ * to the OS/driver.
+ */
+static int bios_with_pstate_cap;
+
+static int bios_capability_found(const struct dmi_system_id *d)
+{
+ bios_with_pstate_cap = 1;
+ printk(KERN_INFO PFX "driver did not load because %s BIOS"
+ " has built-in pstate transitioning"
+ " capability\n", d->ident);
+ return 0;
+}
+
+static const struct dmi_system_id bios_cap_dmi_table[] = {
+ {
+ .callback = bios_capability_found,
+ .ident = "HP ProLiant",
+ .matches = {
+ DMI_MATCH(DMI_SYS_VENDOR, "HP"),
+ DMI_MATCH(DMI_PRODUCT_NAME, "ProLiant DL365"),
+ },
+ },
+ {
+ .callback = bios_capability_found,
+ .ident = "HP ProLiant",
+ .matches = {
+ DMI_MATCH(DMI_SYS_VENDOR, "HP"),
+ DMI_MATCH(DMI_PRODUCT_NAME, "ProLiant DL385"),
+ },
+ },
+ {
+ .callback = bios_capability_found,
+ .ident = "HP ProLiant",
+ .matches = {
+ DMI_MATCH(DMI_SYS_VENDOR, "HP"),
+ DMI_MATCH(DMI_PRODUCT_NAME, "ProLiant BL465c"),
+ },
+ },
+ {
+ .callback = bios_capability_found,
+ .ident = "HP ProLiant",
+ .matches = {
+ DMI_MATCH(DMI_SYS_VENDOR, "HP"),
+ DMI_MATCH(DMI_PRODUCT_NAME, "ProLiant BL495c"),
+ },
+ },
+ {
+ .callback = bios_capability_found,
+ .ident = "HP ProLiant",
+ .matches = {
+ DMI_MATCH(DMI_SYS_VENDOR, "HP"),
+ DMI_MATCH(DMI_PRODUCT_NAME, "ProLiant DL585"),
+ },
+ },
+ {
+ .callback = bios_capability_found,
+ .ident = "HP ProLiant",
+ .matches = {
+ DMI_MATCH(DMI_SYS_VENDOR, "HP"),
+ DMI_MATCH(DMI_PRODUCT_NAME, "ProLiant BL685c"),
+ },
+ },
+ {
+ .callback = bios_capability_found,
+ .ident = "HP ProLiant",
+ .matches = {
+ DMI_MATCH(DMI_SYS_VENDOR, "HP"),
+ DMI_MATCH(DMI_PRODUCT_NAME, "ProLiant DL785"),
+ },
+ },
+ { }
+};
+
/* per CPU init entry point to the driver */
static int __cpuinit powernowk8_cpu_init(struct cpufreq_policy *pol)
{
static const char ACPI_PSS_BIOS_BUG_MSG[] =
KERN_ERR FW_BUG PFX "No compatible ACPI _PSS objects found.\n"
FW_BUG PFX "Try again with latest BIOS.\n";
+ static int done;
struct powernow_k8_data *data;
struct init_on_cpu init_on_cpu;
int rc;
@@ -1271,7 +1348,12 @@ static int __cpuinit powernowk8_cpu_init(struct cpufreq_policy *pol)
* an UP version, and is deprecated by AMD.
*/
if (num_online_cpus() != 1) {
- printk_once(ACPI_PSS_BIOS_BUG_MSG);
+ if (!done) {
+ dmi_check_system(bios_cap_dmi_table);
+ done++;
+ }
+ if (!bios_with_pstate_cap)
+ printk_once(ACPI_PSS_BIOS_BUG_MSG);
goto err_out;
}
if (pol->cpu != 0) {
--
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