PATCH/RFC [0/3]: Fix suspend and other acceleromter issues
Simon Kagstrom
simon.kagstrom at gmail.com
Sun Nov 16 14:25:15 CET 2008
On Sun, 16 Nov 2008 11:18:26 -0200
Werner Almesberger <werner at openmoko.org> wrote:
> Simon Kagstrom wrote:
> > Well, we don't set the LIR bit when configuring FF_WU_CFG. It's also
> > not used for "normal" data-ready interrupts, only with the threshold
> > stuff. So it's already cleared :-)
>
> Ah, that makes sense, yes. So no luck then and AOI doesn't help
> either, grr :-(
Not so fast! :-) Did a bit of testing, and setting the LIR bit when
enabling data collection with the threshold set to 1 (18mg) and at the
same time reading FF_WU_SRC in the interrupt handler makes the
interrupt load more reasonable again:
Cpu(s): 14.2%us, 19.1%sy, 0.0%ni, 47.2%id, 0.0%wa, 0.0%hi, 19.4%si, 0.0%st
Mem: 119968k total, 106472k used, 13496k free, 1032k buffers
Swap: 0k total, 0k used, 0k free, 67304k cached
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
1740 root 20 0 5176 2980 1768 S 18.1 2.5 0:36.22 python
1732 root 20 0 2264 844 684 S 17.1 0.7 0:27.63 dropbear
(same %si load but lower %us load than with the data ready interrupt).
So the LIR bit is probably a good idea and makes sense. Patch coming up
later.
Thanks for the hint Werner!
// Simon
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