[DRM] Failed to implement "DSI to eDP bridge driver"(kernel_imx/drivers/gpu/drm/bridge)

[KyleChang]

We implement "DSI to eDP bridge driver" on i.MX8MQ platform and encounter the following error log:

[drm:nwl_dsi_probe] Using DCSS as input source
[drm] Initialized imx-dcss 1.0.0 20190917 for 32e00000.display-controller on minor 0
[drm] kms: can't enable cloning when we probably wanted to.

We already make sure that test pattern can work as the figure below.

But we don't know how to configure DRM & KMS on i.MX8MQ platform correctly.

Do you have any suggestions to fix the error message below?
[drm] kms: can't enable cloning when we probably wanted to.

or could you please give me documents about DRM porting guide for i.MX8MQ?

BTW, could you please take a look the figure below, we thought there are no problems with MIPI-DSI signal and link training.

[KyleChang]

We bring-up i.MX8MQ+LT8911EXB.

Thank you for your help, please close the ticket.

[joanxie · Accepted solution]

what converter do you use, maybe you can refer to the link as below:

"https://community.nxp.com/t5/i-MX-Processors-Knowledge-Base/IMX8MP-MIPI-DSI-to-eDP-bridge-board-supp..."

[KyleChang]

We use LT8911EXB MIPI DSI to eDP bridge.

The patch does not configure &dcss of device tree on i.MX8MP platform,
but i.MX8MQ must configure &dcss as the figure below.
So I don't know how to configure &dcss correctly, Do you have any suggestions?

[joanxie]

in fact imx8mq can support DP, why do you need use DSI to DP bridge?

[KyleChang]

why do you need use DSI to DP bridge?
=>Please see the following figure.

We refer to imx8mp_ite6151.patch to porting LT8911EXB driver on i.MX8MQ platform,
but Android 11 codebase will compile Error when add
#include <drm/drmP.h> // fatal error: 'drm/drmP.h' file not found
drm_panel_get_modes(); // error: too few arguments to function call, expected 2, have 1
drm_panel_attach(); // error: implicit declaration of function 'drm_panel_attach'
drm_panel_detach();

[joanxie]

I don't have dcss for dsi to eDP bridge, imx8mp doesn't have dcss, only lcdif, in fact, imx8mq has lcdif too, maybe you can use lcdif to replace dcss, another option is that you can use one eDP display on imx8mq eDP port directly, another lvds to mipi dsi port

[KyleChang]

we can bring up LVDS panel(DSI to eDP bridge, GM8775C) using LCDIF as input source successfully.
imx8mp_ite6151.patch can't find how to configure &lcdif for eDP(1920*1080@60).

Could you please give me the device tree of &lcdif for eDP interface, thanks.

[joanxie]

I mailed to you, pls check it

[MJD]

HI @joanxie 
We are using same DSI to eDp Bridge driver with IMX8MP, Yocto Kernel version 6.1.55.
Can you please share the DTs Configuration. 

[joanxie]

mailed to you, pls check it

[joanxie]

this patch is for imx8mp, imx8mq has different IP, let me confirm from LTE if they have verified this on imx8mq processor