From: Nathan Chancellor <natechancellor@gmail.com>
To: Douglas Anderson <dianders@chromium.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Nick Desaulniers <ndesaulniers@google.com>,
robdclark@chromium.org, Akash Asthana <akashast@codeaurora.org>,
jwerner@chromium.org, Andy Gross <agross@kernel.org>,
Bjorn Andersson <bjorn.andersson@linaro.org>,
Jiri Slaby <jirislaby@kernel.org>,
linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-serial@vger.kernel.org
Subject: Re: [PATCH] tty: serial: qcom_geni_serial: 115.2 is a better console default than 9600
Date: Fri, 11 Sep 2020 08:55:42 -0700 [thread overview]
Message-ID: <20200911155542.GA4037107@ubuntu-n2-xlarge-x86> (raw)
In-Reply-To: <20200911080054.1.I4c00b921c2f17b6988688046fa7be0f729f8d591@changeid>
On Fri, Sep 11, 2020 at 08:00:57AM -0700, Douglas Anderson wrote:
> Commit c5cbc78acf69 ("tty: serial: qcom_geni_serial: Initialize baud
> in qcom_geni_console_setup") fixed a bug by initting a variable that
> was used in some cases without initialization. However, the "default"
> baud rate picked by that CL was probably not the best choice. The
> chances that anyone out there is trying to run a system with kernel
> messages piped out over a 9600 baud serial port is just about nil.
> Console messages are printed in a blocking manner. At 9600 baud we
> print about 1 character per millisecond which means that printing a
> 40-byte message to the console will take ~40 ms. While it would
> probably work, it's going to make boot _very_ slow and probably cause
> the occasional timeout here and there in drivers (heck, even at 115200
> console delays can wreck havoc).
>
> This has already bit at least two people that I'm aware of that tried
> to enable serial console by just adding "console=ttyMSM0" (instead of
> "console=ttyMSM0,115200n8") to the command line, so it seems like it'd
> be nice to fix.
>
> Let's switch the default to 115200.
>
> Signed-off-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
> ---
>
> drivers/tty/serial/qcom_geni_serial.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/tty/serial/qcom_geni_serial.c b/drivers/tty/serial/qcom_geni_serial.c
> index f0b1b47c3abc..e390ffc8bbbd 100644
> --- a/drivers/tty/serial/qcom_geni_serial.c
> +++ b/drivers/tty/serial/qcom_geni_serial.c
> @@ -1107,7 +1107,7 @@ static int qcom_geni_console_setup(struct console *co, char *options)
> {
> struct uart_port *uport;
> struct qcom_geni_serial_port *port;
> - int baud = 9600;
> + int baud = 115200;
> int bits = 8;
> int parity = 'n';
> int flow = 'n';
> --
> 2.28.0.618.gf4bc123cb7-goog
>
next prev parent reply other threads:[~2020-09-11 15:56 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-11 15:00 [PATCH] tty: serial: qcom_geni_serial: 115.2 is a better console default than 9600 Douglas Anderson
2020-09-11 15:55 ` Nathan Chancellor [this message]
2020-09-14 9:59 ` Akash Asthana
2020-09-14 15:39 ` Bjorn Andersson
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20200911155542.GA4037107@ubuntu-n2-xlarge-x86 \
--to=natechancellor@gmail.com \
--cc=agross@kernel.org \
--cc=akashast@codeaurora.org \
--cc=bjorn.andersson@linaro.org \
--cc=dianders@chromium.org \
--cc=gregkh@linuxfoundation.org \
--cc=jirislaby@kernel.org \
--cc=jwerner@chromium.org \
--cc=linux-arm-msm@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-serial@vger.kernel.org \
--cc=ndesaulniers@google.com \
--cc=robdclark@chromium.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).