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Old 06-14-2017, 04:19 AM   #1
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Registered: Jun 2017
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Why don't my mipi dsi display show up in dmesg?


I am trying to make a mipi dsi display work with an imx7 using Yocto.
The problem is that I have not been able to get any output in dmesg relating to mipi dsi except "backlight supply power not found" and "MIPI DSI driver module loaded". These two lines are the same no matter if the display are connected or not, and the driver module line shows up two times.
I have been working on this problem for weeks and have tried everything I can think of or find on forums, now I have been stuck for a couple of weeks without any progress.

How do I make the board probe for a mipi driver?
Old 06-26-2017, 03:03 AM   #2
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Registered: Jun 2017
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Bitbake configuration issue?

While editing my device tree to figure this problem out, I run a new menuconfig. In there I believe I altered some minor options I did not expect to make a difference, that was something like a few extra backlight drivers I enabled and some voltage regulators, not really sure witch.
Anyway, this actually helped, the device tree blob for mipi dsi (inx7d-sdb-mipi-dsi.dts) actually compiled and gav me errors which was really helpful. I corrected some errors there and got it compiled, then the dmesg output relating to mipi was the following:

mxc_mipi_dsi_samsung 30760000.mipi-dsi: failed to read lcd_panel property
mxc_mipi_dsi_samsung: probe of 30760000.mipi-dsi failed with error -22

Unfortunately, the compiling of the device tree seems to stop, and I have not been able to reproduce this by changing the configurations.. Does anyone have any ideas to what may be causing this problem? I even tried to introduce errors in the device tree to force a compilation error, this did not work so I am reasonably certain that the device tree relating to mipi does not compile.

Also if anybody know what may cause the dmesg output I got, that may also be helpful, provided that I can get the device tree compiling again.
Old 07-04-2017, 09:28 AM   #3
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Registered: Jun 2017
Posts: 3

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I have limited progress on this project, I have decided to keep a copy of the kernel source in a git repository and edit the files there, this was chosen to keep track of what I am doing.
The device tree now seems to compile fine, but nothing more happens. I assume this to be due to problems with my device tree, but I am not familiar enough with this yet to be sure of what I am missing.
Does anyone have suggestions to what might be missing?
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