SDIO Performance once again

Dominik S. Herwald lists at
Mon Feb 9 08:09:24 EST 2009

Sven Neumann schrieb:
> Hi,
> On Sun, 2009-02-08 at 17:56 +0100, Dominik S. Herwald wrote:
>> right now I am testing Marvell 8686 based Modules connected to the SDIO
>> Controller of a Blackfin BF548.
>> Basically the libertas driver works just fine and stable.  
>> But the Performance... :-/ 
> Interesting. We are having the contrary experience here. Running a
> CM-X300 board, which is a PXA 300 featuring a Marvell 8686 module
> connected to the SDIO controller, we are seeing a performance of about
> 13 Mbits/sec.
> Unfortunately this is not stable. Sometimes (rarely on one of the two
> boards we have, frequently on the other), there are errors:
> libertas: tx watch dog timeout

Hi Sven,

well I've let the module run (and transfer data) for a few hours and did 
never experience a crash.
But only at 3 MBit/s.


In the meantime I found out that my Problem seems to be related to the 
Kernel timer tick of 4ms
(see my second posting on this list with the 4ms frames)...
On Blackfin the Timer tick is set to 250Hz (4ms) by default. If I set it 
to 1000Hz,
performance rises up to 11.2MBit/s performance!

I am still searching for the root of this Problem as setting the timer 
to 1000Hz is no real solution...

Best regards,

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