Comment 39 for bug 1917813

I found this thread:
https://patchwork.<email address hidden>/

And somehow figured out that a i5-10600K is COMETLAKE, and so did the same as that link:

doug@s19:~/temp-k-git/linux$ git diff
diff --git a/drivers/idle/intel_idle.c b/drivers/idle/intel_idle.c
index 3273360f30f7..770660d777c4 100644
--- a/drivers/idle/intel_idle.c
+++ b/drivers/idle/intel_idle.c
@@ -1155,6 +1155,7 @@ static const struct x86_cpu_id intel_idle_ids[] __initconst = {
        X86_MATCH_INTEL_FAM6_MODEL(KABYLAKE_L, &idle_cpu_skl),
        X86_MATCH_INTEL_FAM6_MODEL(KABYLAKE, &idle_cpu_skl),
        X86_MATCH_INTEL_FAM6_MODEL(SKYLAKE_X, &idle_cpu_skx),
+ X86_MATCH_INTEL_FAM6_MODEL(COMETLAKE, &idle_cpu_skl),
        X86_MATCH_INTEL_FAM6_MODEL(ICELAKE_X, &idle_cpu_icx),
        X86_MATCH_INTEL_FAM6_MODEL(XEON_PHI_KNL, &idle_cpu_knl),
        X86_MATCH_INTEL_FAM6_MODEL(XEON_PHI_KNM, &idle_cpu_knl),

And got back the original types of idle states.
I do not want beat up my nvme drive with dbench, so installed an old intel SSD I had lying around:

Phoronix dbench 1.0.2 0 client count 1: (MB/S)
Intel_pstate HWP enabled, active powersave:

Kernel 5.12-rc2 stock:
All idle states enabled: 416.5
Only Idle State 0: 400.1
Only Idle State 1: 294.2
Only idle State 2: 401.6
Only idle State 3: 403.0

Kernel 5.12-rc2 patched as above:
All idle states enabled: 396.8
Only Idle State 0: 400.4
Only Idle State 1: 294.4
Only idle State 2: 245.9
Only idle State 3: 405.3
Only idle State 4: 402.8
quick test: FAIL.

Intel_pstate HWP disabled, active powersave:
Kernel 5.12-rc2 patched as above:
All idle states enabled: 340.0
Only Idle State 0: 399.5
Only Idle State 1: 358.5
Only idle State 2: 353.1
Only idle State 3: 346.9
Only idle State 4: 344.2
quick test: PASS.