No output on console despite ignore_loglevel earlyprintk

[Marc Gonzalez]

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

> Hi,
> 
> Am 03.03.2017 um 17:42 schrieb Marc Gonzalez:
>> 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"
> [...]
>> [    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"
> [...]
>> [    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.
> 
>> 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.