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Stripping IMX7 Sabre boards device tree config crashes the device

Question asked by Arnout Diels on Sep 21, 2016
Latest reply on Sep 21, 2016 by igorpadykov



I am trying to strip the device tree config (imx7-dtb.dts), and work from there, adding only what I would need.


I noticed though, that with my stripped config, the sabre development board crashes very weirdly, but consistently, a few seconds after the login prompt is seen. Sometimes it also just freezes during a crashdump, and sometimes it does not show anything at all.


I worked back, and tried to identify the part of the DTS that could not be "missed". It turns out to be the following:


&lcdif {
     pinctrl-names = "default";
     pinctrl-0 = <&pinctrl_lcdif_dat
     pinctrl-assert-gpios = <&gpio_spi 7 GPIO_ACTIVE_HIGH>;
     display = <&display0>;
     status = "okay";

     display0: display {
          bits-per-pixel = <16>;
          bus-width = <24>;
          display-timings {
               native-mode = <&timing0>;
               timing0: timing0 {
               clock-frequency = <9200000>;
               hactive = <480>;
               vactive = <272>;
               hfront-porch = <8>;
               hback-porch = <4>;
               hsync-len = <41>;
               vback-porch = <2>;
               vfront-porch = <4>;
               vsync-len = <10>;
               hsync-active = <0>;
               vsync-active = <0>;
               de-active = <1>;
               pixelclk-active = <0>;


If I put the status to disabled, or just remove the entire subsystem, the devboard crashes. With it still in place (but the rest heavily stripped), everything runs "quite" fine. 


My question:


Why is this needed? And why is seeminly memory extermely corrupted when removing this?



In attachment, you can find a DTS that works, and one that does not.


Thanks in advance for your reply!


Kind regards,


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