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Raspberry Pi 2, noobs GUI, powered J5create HDMI adaptor going to an old GatewayFPD1750.

The Xorg server blanks the screen after about 10 minutes. I can mess with that timing as described here: Disable screen blanking in X-Windows on Raspbian

Trouble is, after a couple hours of unuse, pressing a key, or moving mouse is no longer enough to bring up the GUI display. If I log in via screen sharing, I can see the mouse move, and letters being typed, the display just doesn't wake. Disconnecting wifi dongle and kybd or mouse does not fix the issue, nor does using a powered USB hub. Unplugging and replugging the HDMI plug does wake the screen, but that's annoying, and what with surface mount there's really no way to solder a switch in there.

However, this pair of terminal commands, entered via the screenshare, will bring back the GUI desktop display for me:

tvservice -p  #(power on hdmi w preferred settings)
xset dpms force on #(turn on HDMI for window server)

Having gotten that far, the question remains: Into which file do I place these commands so that they are always executed when the screen is blank and a key is pressed?

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  • I edited the first and last lines here lest we spread apocryphal rumors about the pi's "low power mode". The pi does not have a low power mode. It is either on, or off. – goldilocks Apr 18 '15 at 14:02
  • @goldilocks OK, I got a little sloppy there. Pi's still new to me. It's a screen blanking feature only. – Wayfaring Stranger Apr 18 '15 at 14:14
  • Do you have another HDMI display you can test this with? – goldilocks Apr 18 '15 at 14:23
  • I don't have this issue w/ a Pi 2 & a Philips 237E, at least initially -- you've said "after several hours of unuse". Does this mean it works when the screen has just gone blank? In that case it's something to do with the pi turning HDMI off after a while...which I guess is obvious. – goldilocks Apr 18 '15 at 14:48
  • I'll drag out a newer monitor to try. Yes, everything's OK for the first hour or so after the screen blanks. Pressing a key will bring it back up. Sometime after that, ~2 hours or so, a kybd press becomes ineffective. It may be some odd powersaving mode on an old monitor, but I'm not finding anything in the display manual or menus. That 2 hour wait makes testing on this absolutely glacial. Still, to the question, there's got to be some file in the raspbian system or windows server that handles what to do when the screen needs de-blanking. If I could find that, I could modify it appropriately – Wayfaring Stranger Apr 18 '15 at 15:00
  • I've posted this on Unix & Linux, but I suspect the answer is no, which makes this more difficult because it's not X that is responsible, it's the pi's hardware. – goldilocks Apr 18 '15 at 15:05
  • Hourly cron, with the appropriate commands, but that seems inelegant. – Wayfaring Stranger Apr 18 '15 at 16:17

1 Answers1

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Significant grepping did not turn up any file with a convenient 'tvservice' containing line. So I found a workaround. First as per goldilocks, I tryed connecting a newer monitor, an Acer S200HQL. The problem went away. Not a practical long term solution here though.

Further experience with the old GatewayFPD1750, revealed that the complete set of commands needed to realiably get the GUI screen to come back up after a prolonged powerdown is:

  • tvservice -o #(power off hdmi)
  • tvservice -p #(power on hdmi w preferred settings)
  • xset dpms force on #(turn on HDMI for window server)

This has worked every time, so far; no unplugging HDMI cord needed. I'd guess that the Raspberry is not properly interfacing with old-school screen sleep tech, so I have to completely turn things off before the display can be reinitiated successfully.

It's easy enough to write a bash script for this in: /usr/local/bin

/#! /bin/bash

tvservice -o
tvservice -p
xset dpms force on

Called the file "wakeolddisplay". Don't forget to chmod a+x the file to make it executable.

Then add a keybinding In the keybindings section of /home/pi/.config/openbox/lxde-pi-rc.xml enter image description here

Now when the screen's asleep, and won't wake up, I just press F6, and the GUI screen comes up, ready for use.

Also made a command, F7, that just powers off HDMI: tvservice -o, as that turns off the ugly and wasteful screen backlighting on this old monitor. An F6 will reverse that as well.

Ghanima
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