Re: [PATCH] ath9k: Add support for Adaptive Power Management

[Mohammed Shafi <mshajakhan@atheros.com>]

On Tuesday 23 November 2010 09:23 PM, Felix Fietkau wrote:
> On 2010-11-23 4:12 PM, Mohammed Shafi Shajakhan wrote:
>    
>> From: Mohammed Shafi Shajakhan<mshajakhan@atheros.com>
>>
>> This feature is to mitigate the problem of certain 3
>> stream chips that exceed the PCIe power requirements.An EEPROM flag
>> controls which chips have APM enabled which is basically read from
>> miscellaneous configuration element of the EEPROM header.
>>
>> This workaround will reduce power consumption by using 2 Tx chains for
>> Single and Double stream rates (5 GHz only).All self generated frames
>> (regardless of rate) are sent on 2 chains when this feature is
>> enabled(Chip Limitation).
>>
>> Cc: Paul Shaw<paul.shaw@atheros.com>
>> Signed-off-by: Mohammed Shafi Shajakhan<mshajakhan@atheros.com>
>> Tested-by: Mohammed Shafi Shajakhan<mshajakhan@atheros.com>I
>>      
> I think this code would get a lot more concise if you'd move it to
> ar9003_mac.c, since this issue is AR9003 specific anyway.
> It would also allow you to avoid adding yet another redundant ath_softc
> capability flag, as the driver part really doesn't need to be concerned
> with this.
>    
Thanks for reviewing the code and for your valuable comments.
1.I get a feeling when we add this to ar9003_mac.c this feature won't be 
much explicit  and might be hard to debug if any issue comes.You might 
have noticed we might be using APM only for non-PAPRD frames.
2.This feature may be applicable for future 3 stream chips (or) in case 
of Power Management we can even disable the third chain (1S and 2S 
rates) while trading of throughput slightly for all 3 stream chips.
3.Yes ath_softc flag might be reduntant I will look into it.
4.There were so many things directly available in xmit.c such as rate 
descriptor,band(5Ghz or 2 Ghz) we are using,whether its a PAPRD frame, 
to looking for single stream and double stream etc.I really dont know 
whether all these things will be available directly available in 
ar9003_mac.c but it would be very difficult to track them and do all the 
right things.
         I will surely look to concise the code in near future , but now 
I think we can have it in upstream.I had tested it and there were no 
issues in fucntionality.
thanks,
shafi

> - Felix
> .
>
>