linux_dsm_epyc7002/drivers/acpi
Stefan Bader 9855d8ce41 ACPI: Check MSR valid bit before using P-state frequencies
To fix incorrect P-state frequencies which can happen on
some AMD systems f594065faf
   "ACPI: Add fixups for AMD P-state figures"
introduced a quirk to obtain the correct values by reading
from AMD specific MSRs.

This did cause a regression when running a kernel using that
quirk under Xen which does (currently) not pass through MSR
reads to the HW. Instead the guest gets a 0 in return.
And this seems to cause a failure to initialize the ondemand
governour (hard to say for sure as all P-states appear to run
at the same frequency).

While this should also be fixed in the hypervisor (to allow
a guest to read that MSR), this patch is intended to work
around the issue in the meantime. In discussion it turned out
that indeed real HW/BIOSes may choose to not set the valid bit
and thus mark the P-state as invalid. So this could be considered
a fix for broken BIOSes that also works around the issue on Xen.

Signed-off-by: Stefan Bader <stefan.bader@canonical.com>
Cc: 3.7+ <stable@vger.kernel.org>
Acked-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-01-22 13:37:21 +01:00
..
acpica
apei ACPI, APEI: Fixup incorrect 64-bit access width firmware bug 2013-01-19 01:34:43 +01:00
ac.c
acpi_i2c.c
acpi_ipmi.c
acpi_memhotplug.c
acpi_pad.c
acpi_platform.c
battery.c
bgrt.c
blacklist.c
bus.c
button.c
cm_sbs.c
container.c
custom_method.c
debugfs.c
device_pm.c
dock.c
ec_sys.c
ec.c
event.c
fan.c
glue.c
hed.c
internal.h
Kconfig
Makefile
numa.c
nvs.c
osl.c
pci_bind.c
pci_irq.c
pci_link.c
pci_root.c
pci_slot.c
power.c
proc.c
processor_core.c
processor_driver.c
processor_idle.c
processor_perflib.c ACPI: Check MSR valid bit before using P-state frequencies 2013-01-22 13:37:21 +01:00
processor_thermal.c
processor_throttling.c
reboot.c
resource.c
sbs.c
sbshc.c
sbshc.h
scan.c
sleep.c
sleep.h
sysfs.c
tables.c
thermal.c
utils.c
video_detect.c
video.c
wakeup.c