[ACPI] Avoid BIOS inflicted crashes by evaluating _PDC only once

Linux invokes the AML _PDC method (Processor Driver Capabilities)
to tell the BIOS what features it can handle.  While the ACPI
spec says nothing about the OS invoking _PDC multiple times,
doing so with changing bits seems to hopelessly confuse the BIOS
on multiple platforms up to and including crashing the system.

Factor out the _PDC invocation so Linux invokes it only once.

http://bugzilla.kernel.org/show_bug.cgi?id=5483

Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
This commit is contained in:
Venkatesh Pallipadi
2005-10-23 16:31:00 -04:00
committed by Len Brown
parent d2149b5423
commit 05131ecc99
16 changed files with 243 additions and 231 deletions

View File

@ -253,31 +253,21 @@ static int acpi_processor_errata(struct acpi_processor *pr)
* _PDC is required for a BIOS-OS handshake for most of the newer
* ACPI processor features.
*/
int acpi_processor_set_pdc(struct acpi_processor *pr,
struct acpi_object_list *pdc_in)
static int acpi_processor_set_pdc(struct acpi_processor *pr)
{
struct acpi_object_list *pdc_in = pr->pdc;
acpi_status status = AE_OK;
u32 arg0_buf[3];
union acpi_object arg0 = { ACPI_TYPE_BUFFER };
struct acpi_object_list no_object = { 1, &arg0 };
struct acpi_object_list *pdc;
ACPI_FUNCTION_TRACE("acpi_processor_set_pdc");
arg0.buffer.length = 12;
arg0.buffer.pointer = (u8 *) arg0_buf;
arg0_buf[0] = ACPI_PDC_REVISION_ID;
arg0_buf[1] = 0;
arg0_buf[2] = 0;
if (!pdc_in)
return_VALUE(status);
pdc = (pdc_in) ? pdc_in : &no_object;
status = acpi_evaluate_object(pr->handle, "_PDC", pdc_in, NULL);
status = acpi_evaluate_object(pr->handle, "_PDC", pdc, NULL);
if ((ACPI_FAILURE(status)) && (pdc_in))
if (ACPI_FAILURE(status))
ACPI_DEBUG_PRINT((ACPI_DB_INFO,
"Error evaluating _PDC, using legacy perf. control...\n"));
"Could not evaluate _PDC, using legacy perf. control...\n"));
return_VALUE(status);
}
@ -574,6 +564,10 @@ static int acpi_processor_start(struct acpi_device *device)
"Error installing device notify handler\n"));
}
/* _PDC call should be done before doing anything else (if reqd.). */
arch_acpi_processor_init_pdc(pr);
acpi_processor_set_pdc(pr);
acpi_processor_power_init(pr, device);
if (pr->flags.throttling) {