Revision as of 02:47, 11 October 2017

References

source code

device-tree document

Tips

Whether eDP display card has been registered successfully

If the eDP display card has been created, it would create a sysfs debug directory.

<code>$ ls /sys/class/drm/card0-eDP-1</code>

So you just need to check that directory. If that directory is missing in your machine board, please check:

• Whether eDP & eDP-PHY have been enabled in DTS files.
• Whether eDP panel have been registered successfully.
• Whether you have available VOP module for eDP.
• Check the kernel log for more detail (dmesg | grep dp)

Check eDP display card status: status, enabled, modes

<code>$ cd /sys/class/drm/card0-eDP-1
$ cat status  # should printed connected or disconnected
$ cat enabled # should printed enabled or disabled
$ cat modes   # should printed the available mode list, like 1536x2048</code>

If you still have no picture on eDP panel, please check bellow information:

• Check the eDP panel power supply.
• Check the panel datasheet, ensure you have configured the timing and power sequence rightly.
• Check the hardware connected status, or test the panel on workable board.