From: Doug Anderson <dianders@chromium.org>
To: Daniel Thompson <daniel.thompson@linaro.org>
Cc: Jason Wessel <jason.wessel@windriver.com>,
Sumit Garg <sumit.garg@linaro.org>,
kgdb-bugreport@lists.sourceforge.net,
linux-serial@vger.kernel.org, LKML <linux-kernel@vger.kernel.org>,
Patch Tracking <patches@linaro.org>
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: <CAD=FV=U64XLRFkTyTi1qDZjTYQKJ9WVBf3OoULpw6yncOQURTg@mail.gmail.com> (raw)
In-Reply-To: <20200430161741.1832050-1-daniel.thompson@linaro.org>
Hi,
On Thu, Apr 30, 2020 at 9:18 AM Daniel Thompson
<daniel.thompson@linaro.org> 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 <daniel.thompson@linaro.org>
> ---
>
> 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 <dianders@chromium.org>
next prev parent 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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