Messages in this thread | | | From | Linus Torvalds <> | Date | Fri, 9 Aug 2019 08:57:13 -0700 | Subject | Re: [RFC PATCH v4 9/9] printk: use a new ringbuffer implementation |
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On Thu, Aug 8, 2019 at 11:14 PM Peter Zijlstra <peterz@infradead.org> wrote: > > Note that you can hook this into printk as a fake early serial device; > just have the serial device write to the DRAM buffer.
No, you really really can't.
Look, the whole point of that reboot buffer is that it works WHEN NOTHING ELSE DOES.
Very much including things like "oh, we're doing a suspend/resume, so the console lock is held to make sure we don't touch any devices that are likely dead right now".
The poweroff buffer is not a console. Don't even try to think of it as one. It's for when consoles don't work. Trying to make it be an early-console would completely defeat the whole point.
Even the "early console" stuff tries to honor serialization by console_lock and console_suspended etc. Or things like the "I'm in the middle of the scheduler, so I won't be doing any real logging".
If the system works, and you get console output or you have a working syslogd that saves messages to disk, all of this is entirely irrelevant. Really.
Don't think of it as a console. If you do, you're doing it wrong.
Linus
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