Re: [PATCH v2 2/2] printk: Add printk.console_verbose boot parameter

[Petr Mladek]

On Tue 2021-07-13 02:15:11, Dmitry Safonov wrote:
> console_verbose() increases console loglevel to CONSOLE_LOGLEVEL_MOTORMOUTH,
> which provides more information to debug a panic/oops.
> 
> Unfortunately, in Arista we maintain some DUTs (Device Under Test) that
> are configured to have 9600 baud rate. While verbose console messages
> have their value to post-analyze crashes, on such setup they:
> - may prevent panic/oops messages being printed
> - take too long to flush on console resulting in watchdog reboot
> 
> In all our setups we use kdump which saves dmesg buffer after panic,
> so in reality those extra messages on console provide no additional value,
> but rather add risk of not getting to __crash_kexec().
> 
> Provide printk.console_verbose boot parameter, which allows to switch off
> printk being verbose on oops/panic/lockdep (making it boot parameter
> instead of compile-option suggested-by Petr).
> 
> Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
> Cc: John Ogness <john.ogness@xxxxxxxxxxxxx>
> Cc: Petr Mladek <pmladek@xxxxxxxx>
> Cc: Sergey Senozhatsky <senozhatsky@xxxxxxxxxxxx>
> Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
> Signed-off-by: Dmitry Safonov <dima@xxxxxxxxxx>

Reviewed-by: Petr Mladek <pmladek@xxxxxxxx>
Tested-by: Petr Mladek <pmladek@xxxxxxxx>

Best Regards,
Petr