Re: PXA27x UDC Power
Alan Stern <[email protected]>
| Newsgroups | gmane.linux.usb.devel |
|---|---|
| Message-ID | <[email protected]> |
On Thu, 29 Nov 2007, Justin Clacherty wrote: > I've implemented this and it seems to work nicely (turning on the > charger anyway). Now how do I go about reducing the draw back to 100 mA > when I'm disconnected so that I'm not still in 500 mA mode when USB is > plugged in again? Do it in your gadget driver's disconect() method. Just call vbus_draw(100). You need to know when disconnects occur anyway, because your driver has to reinitialize itself. > I was initially expecting that vbus_draw would be called with a mA value > of 100 or less when disconnecting but this doesn't seem to be the case. > I can't use vbus_session as we don't monitor vbus on our product. Is > there some other function that's likely to be called on disconnect that > can be used to trigger a reduction in current draw? IMO it's a bug if the controller driver doesn't reduce the current draw back to 100 mA after a disconnect/reconnect cycle. (It also is up to the controller driver to reduce the draw during a USB suspend.) This bug may be present in many of the drivers. A little auditing would be in order. Alan Stern ------------------------------------------------------------------------- SF.Net email is sponsored by: The Future of Linux Business White Paper from Novell. From the desktop to the data center, Linux is going mainstream. Let it simplify your IT future. http://altfarm.mediaplex.com/ad/ck/8857-50307-18918-4 _______________________________________________ [email protected] To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel