On 1/7/21 7:48 PM, Sergey Senozhatsky wrote:

On (21/01/07 09:58), Vineet Gupta wrote:

quoted

On 1/7/21 9:04 AM, Petr Mladek wrote:

quoted

On Thu 2021-01-07 08:43:16, Vineet Gupta wrote:

quoted

Hi John,

On 1/7/21 1:02 AM, John Ogness wrote:

quoted

Hi Vineet,

On 2021-01-06, Vineet Gupta [off-list ref] wrote:

quoted

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.

I wonder if we'll move the nulltty fallback logic into printk code [1]
will it fix the problem?

[1] https://lore.kernel.org/lkml/X6x%2FAxD1qanC6evJ at jagdpanzerIV.localdomain/

Your reasoning in the post above makes total sense.

I tired the patch: adding register_ttynull_console() call in 
console_device(), removing from console_on_rootfs() band that works too.


| Warning: unable to open an initial console. Fallback to ttynull.
| Warning: Failed to add ttynull console. No stdin, stdout, and stderr 
for the init process!
| Freeing unused kernel memory: 3096K
| This architecture does not have kernel memory protection.
| Run /init as init process
| with arguments:
|    /init
|  with environment:
|    HOME=/
|    TERM=linux
| Starting System logger (syslogd)
| Bringing up loopback device
| Starting inetd
| Mounting Posix Mqueue filesys
| 
CONFIG_INITRAMFS_SOURCE="~/arc/RAMFS/archs/ramfs_2011-GNU-2020-03-glibc-2.32-tiny"
| **********************************************************************
|			Welcome to ARCLinux
| **********************************************************************
| [ARCLinux]#