WLAN Horrible Roaming Performance (N800, OS2008), Software or Hardware Problem ?

[Frantisek Dufka]

Kalle Valo wrote:
> What
> you are missing that in N800 there are two extra kernel processes
> running. 770 version does not use any kernel processes (a tasklet is
> not a process, basically).

I see. Only 770 version uses tasklets. Now it is clear again :-)

> Do I make any sense?

Yes, perfect sense. Thank you. I already started another mail with same 
findings - spi_sync implementation calls wait_for_completion 
http://lxr.linux.no/linux+v2.6.21/drivers/spi/spi.c#L514
which sleeps - http://lwn.net/Articles/23993/

So we could start similar processes in 770 version too and use same 
mechanism and get rid of this busy looping too.

According to my previous tests
http://bugs.maemo.org/show_bug.cgi?id=2006#c47
I got maximum of 305 udelay(5) loops for reading and 3819 udelay(5) 
loops for writing so that's 19 miliseconds of busylooping in worst case 
for writing (if udelay counts in microseconds). So this might be worth 
the effort.

Frantisek