[Gta04-owner] [PATCH 2/3] ASoC: twl4030: allow voice port to be connected externally.

Radek Polak psonek2 at seznam.cz
Mon Nov 17 20:02:47 CET 2014


On Sunday, November 16, 2014 07:00:42 PM Dr. H. Nikolaus Schaller wrote:

> Am 12.11.2014 um 06:37 schrieb NeilBrown <neilb at suse.de>:
>
> > device is closed, the hso driver tells the usb
> > bus that everything is inactive, and the usb bus powers down.  That tells
> > the hso driver to power down, and it fiddles with the GPIO lines as
> > required. The hso device would be marked to persisted so the  devices
> > remain.
> 
> Now, I get your general idea:
> 
> * a device is powered on only if there is a user space client that accesses
> it * access is detected through an open() for some control interface
> 
> This is indeed a good approach for fully automatic power management.
> But it might be very difficult to implement.

Hmm for some reason QtMoko closes the serial port before suspend [1]. I was 
probably getting missed calls when it was opened in suspend [2]. Maybe this is 
now not relevant anymore. Still i think there might be some use cases when you 
want to have the modem powered independently on port open - but sure they are 
quite rare...

BR

Radek

[1] 
https://github.com/radekp/qtmoko/blob/master/devices/gta04/src/plugins/phonevendors/neo/vendor_neo.cpp#L236

[2] 
https://github.com/radekp/qtmoko/commit/5fc8bfc6976f8a76c4b02707a82e9012fdc92487


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