No output on console despite ignore_loglevel earlyprintk
Marc Gonzalez
marc_gonzalez at sigmadesigns.com
Fri Mar 3 09:07:39 PST 2017
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 = ð0;
};
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.
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