IMX6UL can't show image after warm reset

[kr90911]

Hi all,

I'm working with IMX6UL and YOCTO sumo 4.14.98.

My device work fine when cold reset(power off and power on), but it can't show any pixel after warm reset.

I found some things about this problem as follow:

1. No matter how to reset device, below boot message will show anyway:

OF: Duplicate name in lcdif@021c8000, renamed to "display#1"
mxsfb 21c8000.lcdif: 21c8000.lcdif supply lcd not found, using dummy regulator
sii902x bound to mxs-lcdif from 21c8000.lcdif
mxsfb 21c8000.lcdif: Unable to allocate overlay fb memory
mxsfb 21c8000.lcdif: failed to map video mem for overlay
mxsfb 21c8000.lcdif: initialized

I don't know if these message are relevant to my problem

2.The attached image will show after boot to user space in cold reset case, but nothing will show after warm reset.

cold reset case

Have anyone encounter this problem?

[jimmychan]

Is there a reset pin on your LCD display? Do you try to reset your LCD when warm reset?

[kr90911 · Accepted solution]

Hi Chen,

Thanks for your reply.

I just found some things and the problem solved.

The LCD reset pin MX6UL_PAD_LCD_RESET is mux as WDOG1_WDOG_ANY, and the pin nevergo high after warm reset, that make LCD always in reset status.

So I comment out watchdog pin in imx6ul-14x14-evk.dts:

pinctrl_wdog: wdoggrp {
fsl,pins = <
//MX6UL_PAD_LCD_RESET__WDOG1_WDOG_ANY 0x30b0
>;
};

and mux MX6UL_PAD_LCD_RESET as GPIO:

pinctrl_lcdif_ctrl: lcdifctrlgrp {
fsl,pins = <
MX6UL_PAD_LCD_CLK__LCDIF_CLK 0x79
MX6UL_PAD_LCD_ENABLE__LCDIF_ENABLE 0x79
MX6UL_PAD_LCD_HSYNC__LCDIF_HSYNC 0x79
MX6UL_PAD_LCD_VSYNC__LCDIF_VSYNC 0x79
/* used for lcd reset */
MX6UL_PAD_LCD_RESET__GPIO3_IO04 0x80000000
//MX6UL_PAD_SNVS_TAMPER9__GPIO5_IO09 0x79
>;
};

 Now the LCD will show graphic after warm reset.