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| author | Bjorn Helgaas <bjorn.helgaas@hp.com> | 2009-05-21 17:28:53 -0600 |
|---|---|---|
| committer | Len Brown <len.brown@intel.com> | 2009-05-27 21:45:53 -0400 |
| commit | bdf43bbf2e19952d82995a50e00cb4b66afa4f0c (patch) | |
| tree | a7e7f84117f6c26c3a0f22439664fb9b4645cbcc /drivers/acpi/power.c | |
| parent | cd86a536c81e9300d984327517548ca0652eebf9 (diff) | |
| download | lwn-bdf43bbf2e19952d82995a50e00cb4b66afa4f0c.tar.gz lwn-bdf43bbf2e19952d82995a50e00cb4b66afa4f0c.zip | |
ACPI: don't check power state after _ON/_OFF
We used to evaluate _STA to check the power state of a device after
running _ON or _OFF. But as far as I can tell, there's no benefit
to evaluating _STA, and sometimes we trip over bugs when BIOSes don't
implement _STA correctly.
Yakui says Windows XP doesn't evaluate _STA during power transition.
So let's skip it in Linux, too. It's conceivable that we'll need to
check _STA in the future for some reason, but until we do, I don't
see a reason to clutter this code path.
References:
http://bugzilla.kernel.org/show_bug.cgi?id=13243
http://marc.info/?l=linux-acpi&m=124166053803753&w=2
http://marc.info/?l=linux-acpi&m=124175761408256&w=2
http://marc.info/?l=linux-acpi&m=124210593114061&w=2
Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Acked-by: Matthew Garrett <mjg59@srcf.ucam.org>
Signed-off-by: Len Brown <len.brown@intel.com>
Diffstat (limited to 'drivers/acpi/power.c')
| -rw-r--r-- | drivers/acpi/power.c | 28 |
1 files changed, 2 insertions, 26 deletions
diff --git a/drivers/acpi/power.c b/drivers/acpi/power.c index 56665a63bf19..d74365d4a6e7 100644 --- a/drivers/acpi/power.c +++ b/drivers/acpi/power.c @@ -194,7 +194,7 @@ static int acpi_power_get_list_state(struct acpi_handle_list *list, int *state) static int acpi_power_on(acpi_handle handle, struct acpi_device *dev) { - int result = 0, state; + int result = 0; int found = 0; acpi_status status = AE_OK; struct acpi_power_resource *resource = NULL; @@ -236,18 +236,6 @@ static int acpi_power_on(acpi_handle handle, struct acpi_device *dev) if (ACPI_FAILURE(status)) return -ENODEV; - if (!acpi_power_nocheck) { - /* - * If acpi_power_nocheck is set, it is unnecessary to check - * the power state after power transition. - */ - result = acpi_power_get_state(resource->device->handle, - &state); - if (result) - return result; - if (state != ACPI_POWER_RESOURCE_STATE_ON) - return -ENOEXEC; - } /* Update the power resource's _device_ power state */ resource->device->power.state = ACPI_STATE_D0; @@ -258,7 +246,7 @@ static int acpi_power_on(acpi_handle handle, struct acpi_device *dev) static int acpi_power_off_device(acpi_handle handle, struct acpi_device *dev) { - int result = 0, state; + int result = 0; acpi_status status = AE_OK; struct acpi_power_resource *resource = NULL; struct list_head *node, *next; @@ -293,18 +281,6 @@ static int acpi_power_off_device(acpi_handle handle, struct acpi_device *dev) if (ACPI_FAILURE(status)) return -ENODEV; - if (!acpi_power_nocheck) { - /* - * If acpi_power_nocheck is set, it is unnecessary to check - * the power state after power transition. - */ - result = acpi_power_get_state(handle, &state); - if (result) - return result; - if (state != ACPI_POWER_RESOURCE_STATE_OFF) - return -ENOEXEC; - } - /* Update the power resource's _device_ power state */ resource->device->power.state = ACPI_STATE_D3; |