Re: Linux-3.14-rc2: Order of serial node compatibles in DTS files.

[Kumar Gala <galak@kernel.crashing.org>]

On Feb 11, 2014, at 2:57 PM, Stephen N Chivers <schivers@csc.com.au> wrote:

> I have been trial booting a 3.14-rc2 kernel for a 85xx platform 
> (dtbImage).
> 
> After mounting the root filesystem there are no messages from the init 
> scripts
> and the serial console is not available for login.
> 
> In the kernel log messages there is:
> 
> of_serial f1004500.serial: Unknown serial port found, ignored.
> 
> The serial nodes in boards dts file are specified as:
> 
>        serial0: serial@4500 {
>                        cell-index = <0>;
>                        device_type = "serial";
>                        compatible = "fsl,ns16550", "ns16550";
>                        reg = <0x4500 0x100>;
>                        clock-frequency = <0>;
>                        interrupts = <0x2a 0x2>;
>                        interrupt-parent = <&mpic>;
>                };
> 
> Reversing the order of the compatible:
> 
>        compatible = "ns16550", "fsl,ns16550";
> 
> restores the serial console.
> 
> Linux-3.13 does not have this behaviour.
> 
> There are 49 dts files in Linux-3.14-rc2 that have the fsl,ns16550 
> compatible first.

Hmm,

Wondering if this caused the issue:

commit 105353145eafb3ea919f5cdeb652a9d8f270228e
Author: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
Date:   Tue Dec 3 14:52:00 2013 +0100

    OF: base: match each node compatible against all given matches first


- k