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AM3358: LCD_VSYNC going low at kernel start

Part Number: AM3358

Tool/software: Linux

I have a custom board running as a Beaglebone Black in TI Linux 3.01.00.06

I have commented out the whole '&am33xx_pinmux', '&lcdc', and '&i2c0' sections in am335x-boneblack.dts to disable hdmi since I don't have the tda chip.

I have set LCD_VSYNC (GPIO2_22) to toggle in u-boot (board.c). I see the pin toggle, but as soon as I see "Starting kernel ..." on the console, the pin goes low. I don't know if it's happening at the end of u-boot, or at the beginning of loading the kernel.

I need it to stay high. I tried adding an LED entry in the device tree to force it high, but that's happening too late in the kernel boot (after USB detection).

This pin is connected to a USB 4G module's reset line and it needs to be high so that Linux detects it on bootup and sets up the ethernet interface. I can set it up manually after, but I'd like it to 'just come up'.

Thanks.