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How can I activate DVI mode in HDMI linux driver?

Question asked by Diego Perez on Nov 7, 2017
Latest reply on Nov 13, 2017 by Diego Perez

Hi,

 

How can I activate DVI mode in HDMI linux driver?

 

I am having problems with HDMI interface. I connect HDMI imxsolo to a HDMI(only audio)/DVI RGB converter (TFP401).

 

TFP401 manage an 800x480 TFT RGB display, so the PCLK, HSYN, VSYNC, and RGB is generated by HDMI to RGB converter. In the images below, the PCLK, HSYNC, VSYNC and EN are measured in the RGB display bus.

 

The issue is that under Linux, the display doesn’t show image (sometimes if I modify timings with “fbset” command I get an instable image with a lot of flickering), the signals seen in the logic analyzer are shown below. HSYNC is missing.

 

Under uboot, I configured an HDMI panel and the results are correct. A nice image without flickering is showed. And the signals are correct.

 

I realized that under uboot the bit DVI_mode of the register HDMI_FC_INVIDCONF is 0 selecting DVI mode, and under linux this bit is 1, so HDMI mode is selected under linux.

 

I suspect DVI_mode bit affects to synchronization signals. So, I would like to enable DVI mode in linux driver to test whether the image and signals are correct as in uboot.

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