On latest git, powertop shows 20 ACPI interrupts per second.  
Previously, this was closer to 1 per second.  See attached output (a vs 
b, "a" is from 2.6.29-rc8).

This is from a pretty sparse KDE desktop.  Normally I run 
gnome-power-manager, but I killed it to make sure that wasn't causing 
any problems.

alan@alan-eeepc:/sys/firmware/acpi/interrupts$ grep -v "invalid" *
error:       0
ff_gbl_lock:       0    enabled
ff_pwr_btn:       0     enabled
ff_rt_clk:       0      disabled
gpe03:       0  disabled
gpe04:       0  disabled
gpe05:       0  disabled
gpe09:       0  disabled
gpe0B:       0  disabled
gpe0C:       0  disabled
gpe0D:       0  disabled
gpe0E:       0  disabled
gpe18:   60975  enabled
gpe_all:   60975
sci:   60975

which I presume means lots of EC interrupts.

[    0.134068] ACPI: EC: GPE = 0x18, I/O: command/status = 0x66, data = 0x62

Any ideas?

Thanks
Alan