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ad7511 PL/driver often no monitor output

Question asked by milosoftware on Aug 13, 2014
Latest reply on Aug 21, 2014 by larsc

I have a problem with the ad7511 HDMI output. This has been present for a long time, it recently got much worse.

 

We use the ADI reference design for the HDMI parts on the FPGA side, and the 3.14 kernel (roughly the adi/xcomm_zynq_new_pcore_regmap branch).

 

When a monitor is connected, and we boot the board, the monitor stays dead, even though the HDMI status reports "connected" correctly.

 

Re-plugging the monitor does not help.

 

If I remove the driver and probe it again, often then mysteriously the monitor reacts. Then either the monitor will turn off again (complaining there's no signal) or it will then just display. There's no output on dmesg. "modprobe -r adi_axi_hdmi ; modprobe adi_axi_hdmi" is the command to re-load the driver.

 

I tried with DELL, HP and IIYAMA monitors. They all behave the same. The HP has a lower resolution, and if I run fbset, I can see that the correct resolution was detected, but there's no signal, even thou

 

What could cause it, and how could I diagnose this further?

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