Stripping IMX7 Sabre boards device tree config crashes the device

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Stripping IMX7 Sabre boards device tree config crashes the device

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arnoutdiels
Contributor III

Hi,

 

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_lcdif_ctrl>;
     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,

Arnout

Original Attachment has been moved to: imx7-sdb--stripped-nocrash.txt.zip

Original Attachment has been moved to: imx7-sdb--stripped-crash-10safterboot.txt.zip

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igorpadykov
NXP Employee
NXP Employee

Hi Arnout

instability maybe caused by pxp which is working in conjunction

with LCDIF. Also one can disable hdmi (sii902x) and check if these

modules are disabled i uboot.

Best regards
igor
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