[Gta04-owner] Modem USB suspend (possible ~80mA reduction on active system?)

Hermann Schwärzler hermann.schwaerzler at chello.at
Mon Jun 2 09:20:07 CEST 2014


On 06/01/2014 12:56 PM, Dr. H. Nikolaus Schaller wrote:
> Some more information. I have checked on the 3.15-rc7 I am currently working on.
> There is only a single power/control node NOT switched to auto:
> root at gta04:~# find /sys -path "*/power/control"|while read FILE; do echo "$FILE" $(cat "$FILE"); done|fgrep -v auto
> /sys/devices/68000000.ocp/48064000.usbhshost/48064800.ehci/usb2/2-2/power/control on
> root at gta04:~# 
> So I suggest to check that on other kernels as well and we should find a more
> specific udev rule (so that it does not trigger for all power/control nodes. Or find
> why the kernel does not initialize it as "auto" right after boot.

Here is the output from my device (gta04a4) with QtMoko - kernel
3.7.0-gta04-qtmoko-v56 - running:

root at neo:~# find /sys -path "*/power/control"| \
while read FILE; do echo "$FILE" $(cat "$FILE"); done|fgrep -v auto
/sys/devices/platform/omap_uart.0/power/control on
/sys/devices/platform/omap_uart.2/power/control on

So the modem is in auto mode but not those uarts.
I just set them to "auto" as well (with no apparent change in power usage).

Power usage is about 390 mA (display on and brightness 100%) or 300 mA
with display switched off.


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