USB and suspend. Will it still charge?

[joerg at openmoko.org]

Am Mi  23. April 2008 schrieb Andy Green:
> Somebody in the thread at some point said:
> | On Tue, 22 Apr 2008 15:42:36 +0100 Andy Green <andy at openmoko.com> babbled:
> |
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> |> Somebody in the thread at some point said:
> |> | This afternoon I recognized my laptop throwing a note about "USB device
> |> | detached" when Freerunner goes suspend.
> |> | Raster knows, at least Windows definitely will power down the
> |> USB-connector
> |> | when it sees USB-disconnect.
> |> |
> |> | Maybe we should investigate this, and should clock down the CPU and
> |> shut off
> |> | LCM, but not go to suspend while charging.
> |> | I should mention I'm not even sure Freerunner did charge at all at this
> |> | moment, just in case this makes a difference.
> |>
> |> What's the actual concern there?  If it is to do with missing charging
> |> state change, the PMU throws an interrupt to the CPU on USB connector
> |> insertion and removal, AFAIK these will cause wake.
> |
> | concern is:
> |
> | we plug in, phone wakes. phone gets bored. phone goes to sleep. uspend
> happens.
> | pc detects device removal. pc powers down usb port. phone does not
> have power
> | from usb. no charging happens.
> 
> Normal PC doesn't "power down USB port" I think you'll find.  The port
> has to be powered to detect next device insertion.
That's what I thought to know about USB. Anyway...


> You can confirm with 
> one of these USB reading lamps for example that have no smarts inside.
> 
> -Andy
>