low throughputs with 14e4:4353

[francesco.gringoli at ing.unibs.it]

On Dec 7, 2011, at 1:01 PM, Rafał Miłecki wrote:

> W dniu 5 grudnia 2011 21:39 użytkownik Rafał Miłecki <zajec5 at gmail.com> napisał:
>> W dniu 29 listopada 2011 22:36 użytkownik Rafał Miłecki
>> <zajec5 at gmail.com> napisał:
>>> I'll give it a rest and will try in next days again.
>> 
>> It really seems it's something spur avoidance related (and so most
>> probably CC PLL related). After applying my patch implementing SPUR
>> avoidance, card stops receiving anything. I'll dig more around it.
> 
> I've found bug in my implementation and fixed it. Today evening I'll
> test if my patch fixes performance anyhow (I need physical access).
Rafal,

I did some mmio traces and checked what happens when changing txpower.

1) values in N-PHY tables 0x1A and 0x1B are changed, e.g., for txpower 5 and txpower 10 they are the same, for txpower 15 they are different so I guess there exist thresholds. Unfortunately I don't even know what these tables are.

2) value in PHY register 0x1ea is changed according to the configured power value. As I can read in specs this is the TX power control target power for both radios: e.g., for txpower 5 => 0x2020, for txpower 10 => 0x2c2c, for txpower 15 => 0x3c3c.

Then I switched to b43 and load a custom firmware to analyze how register 0x1ea is setup and it holds always 0x0000. I forced it to be 0x2c2c and magically the throughput increased to ~ 3Mb/s. Unfortunately when I try 0x3c3c (corresponding to txpower 15) I get only phy-transmission errors.

Hope can help.
-Francesco