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From: Doug Anderson <>
To: Daniel Thompson <>
Cc: Jason Wessel <>,
	Sumit Garg <>,,, LKML <>,
	Patch Tracking <>
Subject: Re: [PATCH v2] serial: kgdboc: Allow earlycon initialization to be deferred
Date: Thu, 30 Apr 2020 09:47:27 -0700	[thread overview]
Message-ID: <> (raw)
In-Reply-To: <>


On Thu, Apr 30, 2020 at 9:18 AM Daniel Thompson
<> wrote:
> Currently there is no guarantee that an earlycon will be initialized
> before kgdboc tries to adopt it. Almost the opposite: on systems
> with ACPI then if earlycon has no arguments then it is guaranteed that
> earlycon will not be initialized.
> This patch mitigates the problem by giving kgdboc_earlycon a second
> chance during console_init(). This isn't quite as good as stopping during
> early parameter parsing but it is still early in the kernel boot.
> Signed-off-by: Daniel Thompson <>
> ---
> Notes:
>     v2: Simplified, more robust, runs earlier, still has Doug's
>         recent patchset as a prerequisite. What's not to like?
>     More specifically, based on feedback from Doug Anderson, I
>     have replaced the initial hacky implementation with a console
>     initcall.
>     I also made it defer more aggressively after realizing that both
>     earlycon and kgdboc_earlycon are handled as early parameters
>     (meaning I think the current approach relies on the ordering
>     of drivers/tty/serial/Makefile to ensure the earlycon is enabled
>     before kgdboc tries to adopt it).
>     Finally, my apologies to Jason and kgdb ML folks, who are seeing
>     this patch for the first time. I copied the original circulation
>     list from a patch that wasn't kgdb related and forgot to update.
>  drivers/tty/serial/kgdboc.c | 41 +++++++++++++++++++++++++++++++++++--
>  1 file changed, 39 insertions(+), 2 deletions(-)

Thanks, this looks great!

Reviewed-by: Douglas Anderson <>

  reply	other threads:[~2020-04-30 16:47 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-04-29 17:08 [PATCH] serial: kgdboc: Allow earlycon initialization to be deferred Daniel Thompson
2020-04-30  0:32 ` Doug Anderson
2020-04-30 10:23   ` Daniel Thompson
2020-04-30 16:17 ` [PATCH v2] " Daniel Thompson
2020-04-30 16:47   ` Doug Anderson [this message]
2020-05-21 17:18     ` Doug Anderson
2020-05-22 15:30       ` Daniel Thompson

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