Redless display!

Hardware related problems and workarounds

Redless display!

Postby xilman » Tue Aug 12, 2014 1:43 pm

This is a cute one. Just powered up the first of four boards for the very first time. Everything whent swimmingly but the display is showing only shades of blue and green. Absolutely no red whatsoever. The Dell monitor, the only one I have with HDMI input, works perfectly with other systems.

Any ideas, other than trying the SD-card in another board, which is next on my list?

The intention was always to run headless anyway, so it's not a big deal.

Paul

Added after preview: the USB kbd and mouse have now stopped working, despite disconnectng and reconnecting.

Added in edit: kbd/mouse now working again after another dis/re-connect cycle. Hmmm...
xilman
 
Posts: 80
Joined: Sat May 10, 2014 8:10 pm
Location: UK

Re: Redless display!

Postby xilman » Tue Aug 12, 2014 2:05 pm

Hmm, perhaps the Dell monitor has broken HDMI input. Same effect with different Parallella board and different HDMI cable.

Now to see whether I can kludge something else together. Might have a HDMI -> something-else converter in my box of bits.
xilman
 
Posts: 80
Joined: Sat May 10, 2014 8:10 pm
Location: UK

Re: Redless display!

Postby xilman » Mon Aug 18, 2014 3:52 pm

Ho hum. On precisely one boot I had a blue-less display. Now back to standard red-less.

I used a TV with HDMI input for a few tests. As expected the quality was completely cruddy. Unexpected was that the outer 5% (a guess, not a measurement) of the display was off-screen. Made selecting panels, menus, etc rather interesting.

I'm really not sure whether to ignore all this as my using cruddy display hardware or whether the the HDMI output from the Parallella isn't 100% standards compliant.
xilman
 
Posts: 80
Joined: Sat May 10, 2014 8:10 pm
Location: UK

Re: Redless display!

Postby 9600 » Mon Aug 18, 2014 7:20 pm

xilman wrote:I'm really not sure whether to ignore all this as my using cruddy display hardware or whether the the HDMI output from the Parallella isn't 100% standards compliant.


AFAIK Parallella uses an Analog Devices supplied HDMI controller core (in the FPGA) and corresponding Linux device driver, together with one of their HDMI transmitter ICs. So, I'd be surprised if it is non-compliant, but then I must admit that I don't know much about HDMI and compliance specifics.

Others have had success with making otherwise problematic displays to work by forcing a different resolution.

Cheers,

Andrew
Andrew Back (a.k.a. 9600 / carrierdetect)
User avatar
9600
 
Posts: 997
Joined: Mon Dec 17, 2012 3:25 am

Re: Redless display!

Postby ach1000 » Mon Aug 18, 2014 8:33 pm

xilman wrote:Ho hum. On precisely one boot I had a blue-less display. Now back to standard red-less.

I used a TV with HDMI input for a few tests. As expected the quality was completely cruddy. Unexpected was that the outer 5% (a guess, not a measurement) of the display was off-screen. Made selecting panels, menus, etc rather interesting.

I'm really not sure whether to ignore all this as my using cruddy display hardware or whether the the HDMI output from the Parallella isn't 100% standards compliant.


The missing 5% is the standard HDMI overscan; and its part of the spec.

http://askubuntu.com/questions/4358/how ... -hdmi-hdtv
ach1000
 
Posts: 3
Joined: Mon Dec 17, 2012 3:25 am


Return to Troubleshooting

Who is online

Users browsing this forum: No registered users and 4 guests

cron