Re: imxfb does not turn on automatically

Hi Sascha,

On Mon, Jan 11, 2016 at 5:16 AM, Sascha Hauer [off-list ref] wrote:

Unfortunately this LCD controller does not have an enable bit. The
controller starts directly when the clocks are enabled. If the clocks
are enabled when the controller is not yet programmed with proper
register values then it just goes into some undefined state. What I
suspect is that the clocks already were enabled before driver probe,
presumably by the bootloader, so the controller is already in undefined
state when entering Linux. Now by dis/enabling the ipg clock you
effectively reset the controller. Since you have programmed it with
valid register values in the mean time it starts working after this
reset.
To verify you could try to disable the LCDC related clock gates with
direct register writes in drivers/clk/imx/clk-imx25.c.

Excellent! I did as you suggested and now the LCD turns on by default.

U-boot was enabling the LCD IPG clock.

Will submit a formal patch soon.

Thanks!