Superpatterns Pat Patterson on the Cloud, Identity and Single Malt Scotch

8Jun/1216

Raspberry Pi fix for HDMI to DVI cable issue

My Raspberry Pi arrived this week. After creating a boot image on an SD card I had lying around (using the excellent RasPiWrite utility), I initially booted it up on my TV, using the composite video output - all working!

Raspberry Pi in text mode

After a little exploration from the command line, startx brought up the GUI.

Raspberry Pi running X

As well as the composite video output, the Raspberry Pi supports HDMI. My monitor (a Viewsonic VX2235WM-3) has VGA and DVI inputs, so I ordered the AmazonBasics HDMI to DVI Cable. Connecting up to my monitor, I was disappointed to see no video signal whatsover - the monitor wasn't seeing the Raspberry Pi at all.

Googling around, I discovered that you can set various configuration options that are read before the Raspberry Pi even boots. With a little experimentation, I found that setting

hdmi_force_hotplug=1

in config.txt solves the problem - I see video output from the moment I power up the Raspberry Pi! This makes sense - the description of hdmi_force_hotplug is "Use HDMI mode even if no HDMI monitor is detected" - I'm guessing the cable is not signalling the presence of a monitor to the Raspberry Pi, so it decides that it doesn't need to send HDMI output.

Watch this space for more Raspberry Pi fun!