Auto detect resolution by EDID in Android 9 or 10 via ADV7535 on IMX8M MINI

[JoeChen]

We are working on an IMX8MMINI board with ADV7535 MIPI-DSI to HDMI chip, and we have met a problem.

SoC: IMX8MMINI

Display chip: ADV7535

Display interface: HDMI

O/S: Android 9 or 10 

Kernel version: 4.14.98 or 5.4.70

Main issue:

We have different types of displays, and we want to use them with the same board, and we do not want to change the display setting in the software.

We set the default resolution in Android at 1080p, but it could not be displayed on a 720p display only when we set the default resolution to 720p.

What we would like to do is the device could be displayed on both 1080p and 720 resolution displays separately.

As we know, ADV7535 could support EDID detection, it could detect the EDID provided from the display and provide the correct resolution, so we would like to use this function; however, when we use the resources provided from NXP(BSP/Device tree), it could not be achieved.

We have checked with Analog Device about this issue, and they provided us with a script file, but we still need an example code for reference.

Could anyone help with this?

Thanks.

[Zhiming_Liu]

The ADV7535 driver in Android9 can support edid function.The drm driver will get correct resolution. So there is no issue in kernel driver.

But in getGUIResolution[vendor/nxp-opensource/imx/display/display/KmsDisplay.cpp] function , we keep 1080p resolution in this function.

You can remove this limitation.