View unanswered posts | View active topics It is currently Fri Sep 20, 2019 11:53 am



Reply to topic  [ 10 posts ] 
 How to power-down an USB port? 
Author Message

Joined: Wed Jul 15, 2009 3:49 pm
Posts: 5
Post How to power-down an USB port?
Hello

I have 2 Fit-PC2s, one with Debian 5.0 and the other with Win XP Pro, so the below question applies to either of that OSes.

And the problem is: I bought an external hard disk, Seagate FreeAgent Xtreme 2TB, which heats up during active usage up to 59 Celsius degrees, and maybe even more.

So I just bought "laptop cooler pad" with 3 fans, powered from USB - however it is loud, so I don't want to use it all the time - instead I figured out a simple heat protection scheme:
- enable disk, disable Seagate autosuspend (using sdparm)
- enable cooler pad (the below question is just about it)
- use it
- enable Seagate autosuspend
- wait 15 minutes
- disable cooler pad

I know, how to do it using e.g. custom /etc/init.d script, except I don't know, how to power down USB port to disable the cooler pad.

The important thing is that this cooler pad doesn't register itself as any device - it's just using generic 100mA power from port.

I tried tricks like that:

http://www.linuxquestions.org/questions ... me-514863/

But it didn't help.

Maybe someone has some other ideas about powering down USB ports on Fit-PC2?


Sun Sep 13, 2009 8:46 am
Profile
Site Admin

Joined: Mon Mar 16, 2009 2:11 pm
Posts: 2340
Post Re: How to power-down an USB port?
USB power in fit-PC2 is fed directly from power supply so it is not disabled in off state.

_________________
-------------------------
Irad Stavi
fit-PC forum admin

-------------------------


Sun Sep 13, 2009 9:20 am
Profile

Joined: Thu Sep 03, 2009 8:58 am
Posts: 12
Post Re: How to power-down an USB port?
Hi,
so there is no way to cut USB 5V power when fit_pc2 is off ? To do you plan to offer such possibility in next BIOS release ?

Our problem is that we use fit pc2 with battery, and have 2 ethernet connection, one through usb-ethernet bridge. Even if fit pc2 is off, the usb-ethernet bridge is still running and decharging battery, and this could bring total battery decharging (and could broke our battery).

I read that you will sold fit-pc with 2 ethernet port soon, that would better for us (because USB can't be cut off). Do you know when it will be available ?


Wed Sep 16, 2009 1:21 pm
Profile
Site Admin

Joined: Mon Mar 16, 2009 2:11 pm
Posts: 2340
Post Re: How to power-down an USB port?
This is not a BIOS setting but the electrical routing of USB power.
The conventional solution is turning-off the USB device (Ethernet adapter in this case) during shutdown.

_________________
-------------------------
Irad Stavi
fit-PC forum admin

-------------------------


Thu Sep 17, 2009 7:15 am
Profile

Joined: Sat Aug 29, 2009 2:06 pm
Posts: 14
Post Re: How to power-down an USB port?
Hi,

I have a problem with the USB power too. I'm using the FIT-PC2 as a CarPC with the power supplied by an intelligent automotive power supply (Minibox M4). This PSU sends a shutdown command over the USB port. Then It waits until the PC powers off by means of the ATX PSON lead.

But the FIT=PC does not have a ATX power connector, so I thought I use the USB 5V lead to control a reed relay to drive the ATX PSON lead. But the 5 Volt is not switched off, even when you enabled the "Let Windows power off this device to save energy" option and even when the FIT PC goes to S3 mode.

I read in this tread that the USB power lead is hard wired to the power supply, so I expect there is no way to power off the USB ports, even when the FIT-PC itself is powered off (by pressing the on / off switch for more then 3 seconds.

Is there any alternative to detect that the FIT-PC is powered off? Any suggestions?

Louk.


Fri Sep 18, 2009 3:06 am
Profile
Site Admin

Joined: Mon Mar 16, 2009 2:11 pm
Posts: 2340
Post Re: How to power-down an USB port?
If possible - wait 2 minutes after giving the command and cut power.
The power used in the 2 minutes is small, and if Windows failed to shut down within 2 minutes it is best to reboot anyway.

_________________
-------------------------
Irad Stavi
fit-PC forum admin

-------------------------


Tue Sep 22, 2009 6:46 am
Profile

Joined: Sat Aug 29, 2009 2:06 pm
Posts: 14
Post Re: How to power-down an USB port?
Thanks Irads,

But that is not the problem: When I switch off the ignition of the car, the PSU sends a hibernate command to the FIT-PC, and then waits until it powers down. After 5 minutes it will cut off the power completely.

In normal situations, this works fine, but in the situation when you have switched off the ignition and switched it on within 5 minutes, the PSU will not switch off the power at all and the FIT-PC won't wake up from hibernation, because it only does that when power is (re-) applied to the unit.

So what I need is any signal to detect that the FIT-PC has completed the shutdown or went into hibernate mode (S3?). This signal can be used to drop the PSON line of the PSU, which will drop the power to the FIT-PC and will switch it on again when the Ignition is switch on.

Maybe one of the signals on the network port (RJ45) is suitable to derive the PSON signal? Or maybe even the (condenser) microphone power on the microphone in jack?

Louk.


Sun Oct 04, 2009 10:52 pm
Profile
Site Admin

Joined: Mon Mar 16, 2009 2:11 pm
Posts: 2340
Post Re: How to power-down an USB port?
Or, find a way to unconditionally cut the power momentarily to fit-PC2 before re-applying power on ignition.

_________________
-------------------------
Irad Stavi
fit-PC forum admin

-------------------------


Mon Oct 05, 2009 4:15 pm
Profile

Joined: Sun Sep 27, 2009 12:47 pm
Posts: 4
Post Re: How to power-down an USB port?
maybe an usb or rj45 "watchdog" or similar

i can't see if true but normaly

Code:
The USB has a start of frame bit (frame packet) or maintenance that are sent periodically on the bus

A high speed bus sends a frame every 125.0 μs ± 62.5 ns.
A full speed bus will send a frame every 1000 ms ± 500 ns.
A low speed bus will have a maintenance device which is a EOP (End Of Packet or End Of Pacquet) every 1ms simply the absence of low speed data.


and rj45 must have similar signal
(need to see eternet spec ^^)


Mon Oct 05, 2009 11:32 pm
Profile

Joined: Sat Aug 29, 2009 2:06 pm
Posts: 14
Post Re: How to power-down an USB port?
Thanks for the info.

I will suggest this to MiniBox (the manufacturer of the M4 PSU), maybe they can add this watchdog to there firmware.

Louk.


Wed Oct 07, 2009 11:30 pm
Profile
Display posts from previous:  Sort by  
Reply to topic   [ 10 posts ] 

Who is online

Users browsing this forum: No registered users and 1 guest


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
cron
Powered by phpBB © 2000, 2002, 2005, 2007 phpBB Group.
Designed by STSoftware for PTF.