Vista dropping extended desktop when using HDMI switch

Discussion in 'Cables & Switches' started by Tony_Mac, Oct 18, 2010.

  1. Tony_Mac

    Tony_Mac
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    I have a Neet 4 x 2 (4 in 2 out) HDMI matrix recently added into my home setup which is causing my extended desktop to go a bit haywire.

    I have a Humax HD-Fox T2 freeview box and a PC connected as sources with an Optoma Projector and Asus LCD monitor connected as displays. You can see a connection diagram as a pdf attachment below.

    My PC has an Asus P5Q-EM motherboard which has onboard graphics with HDMI and DVI-D output (there is also onboard VGA out but I don’t use this).

    My “normal” config is to have Windows (Vista 32 bit Premium) running in extended desktop mode, with a movie playing full screen on the projector (usually VLC or XBMC) and the Asus LCD as windows primary display showing the taskbar, desktop widgets etc. The problem arises when I switch the projector over to source 2 (Humax freeview box). At this point Vista seems to drop the projector display altogether and push any programs that were running on there back on to the Asus monitor. If I then set the source for the projector back to the PC windows does recognise that the second display is there again but it doesn’t automatically push XBMC back.

    Does anyone know of a way whereby you can force windows to keep a second display active even if its disconnected? I see there is some kind of DVI-D detective box which will achieve this for DVI-D connections but ideally I’d like to achieve the same result but using an HDMI type and also I’d rather it was a software fix rather than having to purchase yet another piece of kit.

    Thanks for reading

    Tony
     

    Attached Files:

  2. Joe Fernand

    Joe Fernand
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    The Gefen HDMI or DVI ‘Detective’ is going to be your best option – the Detective units are EDID grabbers and will fool the PC into thinking the monitor is always there.

    Worth ensuring you get one on Sale or Return as they work most but not all of the time in this type of scenario!

    Gefen, LLC - HDMI Detective Plus

    Joe
     
  3. Tony_Mac

    Tony_Mac
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    Hi Joe thanks for posting back, I was thinking that this issue was probably gonna mean spending another ~£100 to rectify :(

    Can you recommend any suppliers who do a "if it doesn't work we take it back no quibble" service? I'd happily pay an extra 10% for something if I know that if it doesn't do exactly what I want it to then I can send it back.

    My worry is that although the Detective may fool the PC into believing the monitor "never goes away" I'm concerned that the HDCP handshake that I'm assuming takes place anytime you switch back to the PC as source may interrupt movie playback. Generally things like XBMC, VLC Player, Windows Media Player etc don't like any kind of "interruptions." However if I find a supplier who is accomodating to returns then I'd happily take the plunge.

    Thanks again, will post back how I get on

    Tony

    PS I'm actually having a separate issue with the HDMI matrix (I won't give you the brand just yet) the projector currently will not resync to the PC once I switch away from it. Switching back to the PC after viewing my HD Freeview box gives blinking and snow on the projector. I have tried swapping out the projector for an LG television which worked without any issue (ignoring the desktop issue) so it suggests that it may be an HDCP issue between the projector & PC whenever the matrix is used (PC and Proj works fine on direct connection). So assuming I can get that issue sorted then I'll be looking at getting the EDID issue resolved. If I can't get the matrix issue sorted I'll hopefully get a refund on it and start again from scratch....
     
  4. Joe Fernand

    Joe Fernand
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    A different Matrix may be worth a go – though you may still have to employ the HDMI Detective to keep the PC happy when you switch away from it!!

    Some Matrix have more than one EDID mode and also Firmware that allows you to try different HDCP strategies – 4 x 2 HDMI Matrix Router switch. 3D ready, 1080P. Route 4 different HD video sources to any 2 HD displays with Digital Optical Audio output. 1RU mount

    The folk who supply the above can also supply the Gefen kit!

    Joe

    PS Optoma projectors can be pretty tricky!!!
     
  5. Tony_Mac

    Tony_Mac
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    Bought a Gefen HDMI Detective plus (which cost nearly 1.5 times the price of the matrix LOL) which solved the desktop problem. Vista thinks the second display is there all the time whether the matrix is routing it to an ACTUAL display or not. I can now play movies in full screen using XBMC on the projector side, switch to the freeview box then switch back and the PC is none the wiser, no freezes glitches or anything.

    Still have a sync issue with my Optoma projector when switching away from the Humax but the workaround is to simply power the Humax down before switching away. NB this didn't happen when i swapped my projector out for a TV that I have elsewhere in the house, so its likely to be as Joe described the "fussiness" of the Optoma.

    Tony
     
  6. mentaliss

    mentaliss
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    SorryTony, I've come to the party late but Im interested as I have the same problem on one HTPC that is connected via HDMI to a Switch box sharing with a Virgin set-top box, two IN sources to One output connected to one TV HDMI input, I'm wondering is this problem occurs in a multi display Graphics card,
    ie: ATI Radeon 5770 as this must have its own display 'EDID Grabber'
    ,
     
  7. Tony_Mac

    Tony_Mac
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    If I understand you correctly you're asking whether the issue would persist with a multi-display graphics card? The answer would be a resounding yes, as in my case I'm using a multi-display graphics card (the onboard intel graphics on the Asus P5Q-EM that I'm using supports at least 2 monitors)

    If you look at my connection diagram (the pdf in the original post) you'll see what I mean.

    As for an ATI card that supports EDID grabbing I'm not sure, I wouldn't have thought it likely, although it certainly would be handy and would save people a fortune on those Gefen units.

    Let me know if I can be of any more help

    Tony
     

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