Messages in this thread | | | From | John Ogness <> | Subject | Re: [RFC 1/2] printk: Add kernel parameter: mute_console | Date | Thu, 22 Oct 2020 16:59:15 +0206 |
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On 2020-10-22, Guenter Roeck <linux@roeck-us.net> wrote: >>> diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt >>> index 02d4adbf98d2..52b9e7f5468d 100644 >>> --- a/Documentation/admin-guide/kernel-parameters.txt >>> +++ b/Documentation/admin-guide/kernel-parameters.txt >>> @@ -2974,6 +2974,12 @@ >>> Used for mtrr cleanup. It is spare mtrr entries number. >>> Set to 2 or more if your graphical card needs more. >>> >>> + mute_console [KNL] >>> + Completely disable printing of kernel messages to >>> + the console. It can still be used as stdin, stdout, > > "to all consoles" > >>> + and stderr for the init process. Also it can be used >>> + for login. >> >> IMHO it would make more sense for this to be a console option: >> >> console=ttyS0,115200,mute >> >> Then other consoles could still exist that are not muted. >> > Then why specify this console in the first place ?
Because you may still want to use it for stdin/stdout/stderr of PID 1 and/or logins. I understood "mute" as meaning the user does not want to see kernel logging. But everything else should still work as usual.
>> On a side note, I am considering proposing something similar for my >> printk-rework efforts. Once console printers are moved to kthreads, some >> users may not care about latencies and instead prefer synchronous >> printing. My idea for this is to provide a "sync" option for the >> console: >> >> console=ttyS0,115200,sync > > The whole point of the exercise is to disable all consoles, including > default ones which are not explicitly specified on the command line.
In that case I think specifying something like:
console=null
makes that most sense. I think implementing a "null console" driver would be quite simple. Then there would be no need for special handling in the printk subsystem.
John Ogness
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