Olimex Support Forum

OLinuXino Android / Linux boards and System On Modules => A20 => Topic started by: Romiin on October 06, 2015, 11:50:37 AM

Title: Problems with monitor connecting via HDMI
Post by: Romiin on October 06, 2015, 11:50:37 AM
Hi!

I'm having problems getting anything to display on my monitor. The monitor is connected from the HDMI output from the Lime2 via an HDMI-DVI adapter into the monitor. No signal is received by the monitor!

I have checked that the board works with by using serial connection to the computer.

Can there be a problem with using an HDMI-DVI adapter? Does the screen need an HDMI input for it to work or is it another problem?

Regards,
Andreas
Title: Re: Problems with monitor connecting via HDMI
Post by: Pawel_W on October 06, 2015, 03:33:43 PM
I had problems with monitors too (signal out of range), so I connected my A20 Lime2 to Full HD TV (Samsung 32").
In my opinion Android on A20 Lime2 produces non-standard HDMI signal that some monitors can't accept, because navigation buttons are partially hidden under the TV frame.
Title: Re: Problems with monitor connecting via HDMI
Post by: lhavc on October 09, 2015, 11:36:25 AM
It was due to incorrect negotiation of monitor acceptable signal, as we know HDMI specification does support both RGB and YCbCr signal, and optional audio data. I found that sunxi HDMI driver may enable audio output for a monitor which only has DVI interface, result in display problem. To solve that a simple way is patch hdmi_core.c in drivers/video/sunxi/hdmi, change "audio_enable" to 0. Also, make sure macro YUV_COLORSPACE is not set, as DVI spec can only accept RGB signal.