x86: fix detection of CONSTANT_TSC bit for AMD CPUs
Commits
- c52f61fcbdb2aa84f0e4d831ef07f375e6b99b2c
(x86: allow TSC clock source on AMD Fam10h and some cleanup)
- e30436f05d456efaff77611e4494f607b14c2782
(x86: move X86_FEATURE_CONSTANT_TSC into early cpu feature detection)
are supposed to fix the detection of contant TSC for AMD CPUs.
Unfortunately on x86_64 it does still not work with current x86/mm.
For a Phenom I still get:
...
TSC calibrated against PM_TIMER
Marking TSC unstable due to TSCs unsynchronized
time.c: Detected 2288.366 MHz processor.
...
We have to set c->x86_power in early_identify_cpu to properly detect
the CONSTANT_TSC bit in early_init_amd.
Attached patch fixes this issue. Following the relevant boot
messages when the fix is used:
...
TSC calibrated against PM_TIMER
time.c: Detected 2288.279 MHz processor.
...
Initializing CPU#1
...
checking TSC synchronization [CPU#0 -> CPU#1]: passed.
...
Initializing CPU#2
...
checking TSC synchronization [CPU#0 -> CPU#2]: passed.
...
Booting processor 3/4 APIC 0x3
...
checking TSC synchronization [CPU#0 -> CPU#3]: passed.
Brought up 4 CPUs
...
Patch is against x86/mm (v2.6.24-rc8-672-ga9f7faa).
Please apply.
Set c->x86_power in early_identify_cpu. This ensures that
X86_FEATURE_CONSTANT_TSC can properly be set in early_init_amd.
Signed-off-by: Andreas Herrmann <andreas.herrmann3@amd.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
1 file changed