* [PATCH 2.6] remove unnecessary check in acpi-cpufreq driver
@ 2004-01-11 21:00 Dominik Brodowski
2004-01-28 22:44 ` Len Brown
0 siblings, 1 reply; 2+ messages in thread
From: Dominik Brodowski @ 2004-01-11 21:00 UTC (permalink / raw)
To: len.brown; +Cc: acpi-devel, cpufreq
The acpi cpufreq driver includes a test at startup which detects whether
ACPI P-States are supported on any CPU, and whether transitions work.
However, this test is faulty: it is only run _after_ the acpi driver is
registered, causing race situations. Also, it doesn't save anything _as_ the
driver is already registered. So, it can safely be removed.
arch/i386/kernel/cpu/cpufreq/acpi.c | 74 ++++--------------------------------
1 files changed, 10 insertions(+), 64 deletions(-)
diff -ruN linux-original/arch/i386/kernel/cpu/cpufreq/acpi.c linux/arch/i386/kernel/cpu/cpufreq/acpi.c
--- linux-original/arch/i386/kernel/cpu/cpufreq/acpi.c 2004-01-11 20:50:52.000000000 +0100
+++ linux/arch/i386/kernel/cpu/cpufreq/acpi.c 2004-01-11 20:57:10.927599960 +0100
@@ -1,9 +1,9 @@
/*
- * acpi_processor_perf.c - ACPI Processor P-States Driver ($Revision: 1.3 $)
+ * acpi-cpufreq-io.c - ACPI Processor P-States Driver ($Revision: 1.3 $)
*
* Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
* Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
- * Copyright (C) 2002, 2003 Dominik Brodowski <linux@brodo.de>
+ * Copyright (C) 2002 - 2004 Dominik Brodowski <linux@brodo.de>
*
* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
*
@@ -641,7 +641,6 @@
acpi_cpufreq_init (void)
{
int result = 0;
- int current_state = 0;
int i = 0;
struct acpi_processor *pr = NULL;
struct acpi_processor_performance *perf = NULL;
@@ -649,9 +648,6 @@
ACPI_FUNCTION_TRACE("acpi_cpufreq_init");
/* alloc memory */
- if (performance)
- return_VALUE(-EBUSY);
-
performance = kmalloc(NR_CPUS * sizeof(struct acpi_processor_performance), GFP_KERNEL);
if (!performance)
return_VALUE(-ENOMEM);
@@ -669,69 +665,19 @@
result = acpi_processor_get_performance_info(&performance[i]);
}
- /* test it on one CPU */
- for (i=0; i<NR_CPUS; i++) {
- if (!cpu_online(i))
- continue;
- pr = performance[i].pr;
- if (pr && pr->flags.performance)
- goto found_capable_cpu;
- }
- result = -ENODEV;
- goto err0;
-
- found_capable_cpu:
-
result = cpufreq_register_driver(&acpi_cpufreq_driver);
- if (result)
- goto err0;
-
- perf = pr->performance;
- current_state = perf->state;
-
- if (current_state == pr->limit.state.px) {
- result = acpi_processor_set_performance(perf, (perf->state_count - 1));
- if (result) {
- ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "Disabled P-States due to failure while switching.\n"));
- result = -ENODEV;
- goto err1;
- }
- }
-
- result = acpi_processor_set_performance(perf, pr->limit.state.px);
if (result) {
- ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "Disabled P-States due to failure while switching.\n"));
- result = -ENODEV;
- goto err1;
- }
-
- if (current_state != 0) {
- result = acpi_processor_set_performance(perf, current_state);
- if (result) {
- ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "Disabled P-States due to failure while switching.\n"));
- result = -ENODEV;
- goto err1;
+ /* unregister struct acpi_processor_performance performance */
+ for (i=0; i<NR_CPUS; i++) {
+ if (performance[i].pr) {
+ performance[i].pr->flags.performance = 0;
+ performance[i].pr->performance = NULL;
+ performance[i].pr = NULL;
+ }
}
+ kfree(performance);
}
-
- return_VALUE(0);
-
- /* error handling */
- err1:
- cpufreq_unregister_driver(&acpi_cpufreq_driver);
-
- err0:
- /* unregister struct acpi_processor_performance performance */
- for (i=0; i<NR_CPUS; i++) {
- if (performance[i].pr) {
- performance[i].pr->flags.performance = 0;
- performance[i].pr->performance = NULL;
- performance[i].pr = NULL;
- }
- }
- kfree(performance);
- printk(KERN_INFO "cpufreq: No CPUs supporting ACPI performance management found.\n");
return_VALUE(result);
}
^ permalink raw reply [flat|nested] 2+ messages in thread* Re: [PATCH 2.6] remove unnecessary check in acpi-cpufreq driver
2004-01-11 21:00 [PATCH 2.6] remove unnecessary check in acpi-cpufreq driver Dominik Brodowski
@ 2004-01-28 22:44 ` Len Brown
0 siblings, 0 replies; 2+ messages in thread
From: Len Brown @ 2004-01-28 22:44 UTC (permalink / raw)
To: Dominik Brodowski; +Cc: ACPI Developers, cpufreq
Accepted into ACPI test tree
http://linux-acpi.bkbits.net/linux-acpi-test-2.6.0
http://linux-acpi.bkbits.net/linux-acpi-test-2.6.1
http://linux-acpi.bkbits.net/linux-acpi-test-2.6.2
This means it will be pulled into AKPM's mm tree on the next update.
thanks Dominik,
-Len
On Sun, 2004-01-11 at 16:00, Dominik Brodowski wrote:
> The acpi cpufreq driver includes a test at startup which detects whether
> ACPI P-States are supported on any CPU, and whether transitions work.
> However, this test is faulty: it is only run _after_ the acpi driver is
> registered, causing race situations. Also, it doesn't save anything _as_ the
> driver is already registered. So, it can safely be removed.
>
> arch/i386/kernel/cpu/cpufreq/acpi.c | 74 ++++--------------------------------
> 1 files changed, 10 insertions(+), 64 deletions(-)
>
> diff -ruN linux-original/arch/i386/kernel/cpu/cpufreq/acpi.c linux/arch/i386/kernel/cpu/cpufreq/acpi.c
> --- linux-original/arch/i386/kernel/cpu/cpufreq/acpi.c 2004-01-11 20:50:52.000000000 +0100
> +++ linux/arch/i386/kernel/cpu/cpufreq/acpi.c 2004-01-11 20:57:10.927599960 +0100
> @@ -1,9 +1,9 @@
> /*
> - * acpi_processor_perf.c - ACPI Processor P-States Driver ($Revision: 1.3 $)
> + * acpi-cpufreq-io.c - ACPI Processor P-States Driver ($Revision: 1.3 $)
> *
> * Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
> * Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
> - * Copyright (C) 2002, 2003 Dominik Brodowski <linux@brodo.de>
> + * Copyright (C) 2002 - 2004 Dominik Brodowski <linux@brodo.de>
> *
> * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> *
> @@ -641,7 +641,6 @@
> acpi_cpufreq_init (void)
> {
> int result = 0;
> - int current_state = 0;
> int i = 0;
> struct acpi_processor *pr = NULL;
> struct acpi_processor_performance *perf = NULL;
> @@ -649,9 +648,6 @@
> ACPI_FUNCTION_TRACE("acpi_cpufreq_init");
>
> /* alloc memory */
> - if (performance)
> - return_VALUE(-EBUSY);
> -
> performance = kmalloc(NR_CPUS * sizeof(struct acpi_processor_performance), GFP_KERNEL);
> if (!performance)
> return_VALUE(-ENOMEM);
> @@ -669,69 +665,19 @@
> result = acpi_processor_get_performance_info(&performance[i]);
> }
>
> - /* test it on one CPU */
> - for (i=0; i<NR_CPUS; i++) {
> - if (!cpu_online(i))
> - continue;
> - pr = performance[i].pr;
> - if (pr && pr->flags.performance)
> - goto found_capable_cpu;
> - }
> - result = -ENODEV;
> - goto err0;
> -
> - found_capable_cpu:
> -
> result = cpufreq_register_driver(&acpi_cpufreq_driver);
> - if (result)
> - goto err0;
> -
> - perf = pr->performance;
> - current_state = perf->state;
> -
> - if (current_state == pr->limit.state.px) {
> - result = acpi_processor_set_performance(perf, (perf->state_count - 1));
> - if (result) {
> - ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "Disabled P-States due to failure while switching.\n"));
> - result = -ENODEV;
> - goto err1;
> - }
> - }
> -
> - result = acpi_processor_set_performance(perf, pr->limit.state.px);
> if (result) {
> - ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "Disabled P-States due to failure while switching.\n"));
> - result = -ENODEV;
> - goto err1;
> - }
> -
> - if (current_state != 0) {
> - result = acpi_processor_set_performance(perf, current_state);
> - if (result) {
> - ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "Disabled P-States due to failure while switching.\n"));
> - result = -ENODEV;
> - goto err1;
> + /* unregister struct acpi_processor_performance performance */
> + for (i=0; i<NR_CPUS; i++) {
> + if (performance[i].pr) {
> + performance[i].pr->flags.performance = 0;
> + performance[i].pr->performance = NULL;
> + performance[i].pr = NULL;
> + }
> }
> + kfree(performance);
> }
> -
> - return_VALUE(0);
> -
> - /* error handling */
> - err1:
> - cpufreq_unregister_driver(&acpi_cpufreq_driver);
> -
> - err0:
> - /* unregister struct acpi_processor_performance performance */
> - for (i=0; i<NR_CPUS; i++) {
> - if (performance[i].pr) {
> - performance[i].pr->flags.performance = 0;
> - performance[i].pr->performance = NULL;
> - performance[i].pr = NULL;
> - }
> - }
> - kfree(performance);
>
> - printk(KERN_INFO "cpufreq: No CPUs supporting ACPI performance management found.\n");
> return_VALUE(result);
> }
>
^ permalink raw reply [flat|nested] 2+ messages in thread
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