Re: [PATCH 8/8] acpi-cpufreq: skip duplicate frequencies

[Alexey Starikovskiy <alexey_y_starikovskiy@linux.intel.com>]

Pallipadi, Venkatesh wrote:
>>> I guess we should compact the whole table rather than adding INVALID
>>> entries. With INVALID entries, we may end up running some redundant
>>> loops table_verify table_target functions later.
>>>
>>> Thanks,
>>> Venki
>>>  
>> there can be inconsistency then BIOS issues notifies, if we 
>> change number of P-states.
>> Keeping them INVALID is safer.
>>
> 
> But, BIOS notification only checks the perf->states structure and does
> not depend on frequency table. Right?
> Also, if notification depends on freq table, we will still have a issue
> with this patch and number_of_P-states_change notification.
> Say we have - 3 GHz, 3 GHz, 3 GHz, 2 GHz as P0, P1, P2, and P3 reported
> by BIOS. And it says P2 as the highest frequency through notify. This
> patch would have made P1 and P2 frequency as INVALID. 
BIOS knows that there are 4 P-states, 3 of them being equal (it populated these values after all).
So if it says we need to set limit to upper 2 equal states -- it is BIOS bug (feature).