Re: [PATCH 4/7] cpufreq: amd-pstate: fix max_perf calculation for amd_get_max_freq()

From: Mario Limonciello
Date: Fri Jan 26 2024 - 10:54:43 EST


On 1/26/2024 02:08, Perry Yuan wrote:
From: Perry Yuan <Perry.Yuan@xxxxxxx>

When CPU core Precision Boost state changed, the max frequency will also
need to be updated according to the current boost state, if boost is
disabled now, the max perf will be limited to nominal perf values.
otherwise the max frequency will be showed wrongly.

What about the previous cppc_req? Shouldn't it be explicitly updated as a result of this too?


Signed-off-by: Perry Yuan <Perry.Yuan@xxxxxxx>
---
drivers/cpufreq/amd-pstate.c | 4 ++++
1 file changed, 4 insertions(+)

diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
index b37bea7440b9..3286d72f375e 100644
--- a/drivers/cpufreq/amd-pstate.c
+++ b/drivers/cpufreq/amd-pstate.c
@@ -599,6 +599,10 @@ static int amd_get_max_freq(struct amd_cpudata *cpudata)
nominal_perf = READ_ONCE(cpudata->nominal_perf);
max_perf = READ_ONCE(cpudata->highest_perf);
+ /* when boost is off, the highest perf will be limited to nominal_perf */
+ if (!global.cpb_boost)
+ max_perf = nominal_perf;
+
boost_ratio = div_u64(max_perf << SCHED_CAPACITY_SHIFT,
nominal_perf);