On 03/03/2017 17:59, Andreas Färber wrote:

Hi,

Am 03.03.2017 um 17:42 schrieb Marc Gonzalez:

quoted

I'm confused about early consoles and earlyprintk, and all that good stuff.
When my kernel panics, I don't get the expected output.

Using "mem=256M ignore_loglevel earlyprintk"

[...]

quoted

[    0.014325] Console: colour dummy device 80x30
[    0.018885] console [tty0] enabled
[    0.022396] bootconsole [earlycon0] disabled

And it hangs there.


If I use an explicit console= configuration, I do see the panic.
Using "mem=256M ignore_loglevel console=ttyS0,115200 earlyprintk"

[...]

quoted

[    0.014325] Console: colour dummy device 80x30
[    0.018899] Calibrating delay loop (skipped), value calculated using timer frequency.. 54.25 BogoMIPS (lpj=90000)

[...]

I have reported a similar phenomenon for multiple new SoCs.

quoted

I suppose this is related to my DT description?

	chosen {
		stdout-path = "serial:115200n8";
	};

Isn't stdout-path = "serial:115200n8" supposed to be equivalent to
console=ttyS0,115200 ?

First of all, that should probably be serial0, and it needs to be
defined as an alias. In my case that's a given.

My DT root node contains

	aliases {
		serial = &uart;
		eth0 = &eth0;
	};

Should I be using serial0 everywhere?
(I thought I could call it "foo", if I wanted.)

And yes, AFAIU stdout-path = "serialX:115200n8" should lead to
ttyFOOX,115200n8 being used, in your case it may be ttyS0.

Regards.