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    SubjectRE: Strange output on the console
    Date
    From: Willy Tarreau
    > Sent: 25 February 2022 06:37
    >
    > On Fri, Feb 25, 2022 at 06:12:35AM +0000, David Laight wrote:
    > > From: Steven Rostedt
    > > > Sent: 25 February 2022 04:01
    > > >
    > > > I've been noticing that my tests have been spitting out strange output on
    > > > the console. It would happen at boot up and then clear up. It looks like
    > > > something screwed up with the serial timing.
    > > >
    > > > Attached is a dmesg of one of my test runs as an example.
    > > >
    > > > I've noticed this on both 32 bit and 64 bit x86.
    > > >
    > > > I haven't had time to look deeper into this, but I figured I let you know
    > > > about it.
    > > >
    > > > And it always seems to happen right after:
    > > >
    > > > Serial: 8250/16550 driver, 4 ports, IRQ sharing enabled
    > > >
    > > > Maybe this is a serial issue and not a printk one? :-/
    > >
    > > Looks very much like the serial baud rate is being reset.
    >
    > I don't think it's the baud rate, characters are still readable, it
    > looks more like a fifo being too short and causing lots of chars to
    > be dropped.

    Just before it recovers there is this output:
    ATaitoscic nitahi tuPiet mfba Ae: aD nCt AH0 nP0
    That is probably 'fifo not enabled'.

    But the earlier output doesn't have many different characters in it.
    Which is typical of the baud rate being wrong.

    David

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