Re: ARC no console output (was Re: [PATCH 1/2] init/console: Use ttynull as a fallback when there is no console)

Peter Korsgaard
2021-01-14T02:12:22Z

>>>>> "Vineet" == Vineet Gupta <vgupta@synopsys.com> writes:

> On 1/7/21 9:04 AM, Petr Mladek wrote:
>> On Thu 2021-01-07 08:43:16, Vineet Gupta wrote:
>>> Hi John,
>>>
>>> On 1/7/21 1:02 AM, John Ogness wrote:
>>>> Hi Vineet,
>>>>
>>>> On 2021-01-06, Vineet Gupta <vgupta@synopsys.com> wrote:
>>>>> This breaks ARC booting (no output on console).
>>>>
>>>> Could you provide the kernel boot arguments that you use? This series is
>>>> partly about addressing users that have used boot arguments that are
>>>> technically incorrect (even if had worked). Seeing the boot arguments of
>>>> users that are not experiencing problems may help to reveal some of the
>>>> unusual console usages until now.
>>>
>>>
>>> Kernel command line: earlycon=uart8250,mmio32,0xf0005000,115200n8
>>> console=ttyS0,115200n8 debug print-fatal-signals=1
>>
>> This is strange, the problematic patch should use ttynull
>> only as a fallback. It should not be used when a particular console
>> is defined on the command line.

> What happens in my case is console_on_rootfs() doesn't find
> /dev/console and switching to ttynull. /dev is not present because
> devtmpfs doesn't automount for initramfs.

But our initramfs/cpio logic ensures that the initramfs has a static
/dev/console device node, so how can that be?

https://git.buildroot.net/buildroot/tree/fs/cpio/cpio.mk#n25

--
Bye, Peter Korsgaard