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ADV7610 HDMI Audio for non-standard mode

Question asked by joshuac on Dec 17, 2015
Latest reply on Jan 14, 2016 by mattp

Hi,

 

We have a host android system outputting HDMI data to an ADV7610 with no EDID connected. The output of the HDMI receiver is connected to an 800x480@60 display. If I boot the system up and use a default display mode, then the HDMI audio works. However the incorrect hardware parameters mean that the video display is incorrect.

 

We calculated the required hardware parameters and I have managed to get the system to display the video correctly on the screen by using the following fb_videomode in my linux kernel:

 

{ NULL, 60, 800, 480, 30030, 88, 40, 33, 10, 128, 2, 0,  FB_VMODE_NONINTERLACED, 0 }


 

However, when I use this mode line rather than one of the default CEA modes, the HDMI audio stops working.

 

I am trying to investigate the root cause of the issue. When I read out the audio packet detection registers from the ADV7610 [HDMI Map, Register 0x18], in both of the situations i get:

 

0x30 when no audio is played

0x31 when audio is played

 

This seems to imply that the chip is detecting the audio stream as "L_PCM or IEC 61937 compressed audio sample packet" in both cases.

 

My question is: could this be an issue with the ADV7610 not being configured to handle non-standard mode configuration?

 

Best Regards,

Josh

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