Current Bootchart / breaking SD boot
joseph at pfeifferfamily.net
Thu Jul 10 01:47:41 CEST 2008
Werner Almesberger writes:
>Michael 'Mickey' Lauer wrote:
>> I could be wrong, but IIRC FSO is powering the modem down if you shut it down
>> from console. gsm0710muxd is issuing AT at POFF once you SIGTERM it.
>That AT at POFF doesn't cut power to the modem. Instead, it tells the
>modem to "power down", i.e., to enter its own standby mode, from
>which it can be awakened by "pressing" the modem's "on" button.
>(That "button" is in fact a transistor controlled by MODEM_ON line
>which connect to the CPU's GPB7.)
>What does cut power to most of the GSM chipset is the GSM_ON line
>which connects to the PMU's GPIO2.
>Alas, the modem's RF amplifier is not controlled by this (it doesn't
>like anything to get between it and the battery), so the GSM
>subsystem cannot be entirely cut off.
I'm confused -- do you mean there is no way to turn off the modem's RF
amp? What do other phones using it do to comply with airplane
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