4.7 regression - ACPICA: Hardware: Enhance acpi_hw_validate_register() with access_width/bit_offset awareness

Mike Galbraith
2016-06-22T07:07:17Z

In my aging (ok old) HP DL980 G7 ->access_width may be either 0 or
max_bit_width, the later inspiring cpufreq to say go away. The below
made box a happy camper again.

ACPI Error: Unsupported register access width: 0x40 (20160422/hwregs-165)

Dinged-up-by: my little hammer
---
drivers/acpi/acpica/hwregs.c | 13 ++++++++++---
1 file changed, 10 insertions(+), 3 deletions(-)

--- a/drivers/acpi/acpica/hwregs.c
+++ b/drivers/acpi/acpica/hwregs.c
@@ -83,7 +83,7 @@ acpi_hw_write_multiple(u32 value,
static u8
acpi_hw_get_access_bit_width(struct acpi_generic_address *reg, u8 max_bit_width)
{
- if (!reg->access_width) {
+ if (!reg->access_width || reg->access_width == max_bit_width) {
if (reg->space_id == ACPI_ADR_SPACE_SYSTEM_IO) {
max_bit_width = 32;
}
@@ -152,9 +152,16 @@ acpi_hw_validate_register(struct acpi_ge
return (AE_SUPPORT);
}

- /* Validate the access_width */
+ /* Validate the access_width, or bit_width for old register descriptors */

- if (reg->access_width > 4) {
+ if ((!reg->access_width || reg->access_width == max_bit_width)) {
+ if (reg->bit_width != 8 && reg->bit_width != 16 &&
+ reg->bit_width != 32 && reg->bit_width != max_bit_width) {
+ ACPI_ERROR((AE_INFO, "Unsupported register bit width: 0x%X",
+ reg->bit_width));
+ return (AE_SUPPORT);
+ }
+ } else if (reg->access_width > 4) {
ACPI_ERROR((AE_INFO,
"Unsupported register access width: 0x%X",
reg->access_width));