From: Stephen Boyd <sboyd@codeaurora.org>
To: Bjorn Andersson <bjorn.andersson@linaro.org>,
Andy Gross <andy.gross@linaro.org>,
David Brown <david.brown@linaro.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Jiri Slaby <jslaby@suse.com>,
"open list:ARM/QUALCOMM SUPPORT" <linux-arm-msm@vger.kernel.org>,
"open list:ARM/QUALCOMM SUPPORT" <linux-soc@vger.kernel.org>,
"open list:SERIAL DRIVERS" <linux-serial@vger.kernel.org>,
open list <linux-kernel@vger.kernel.org>
Subject: Re: [RFC PATCH] tty: serial: msm_serial: Don't reset uart on set_termios
Date: Wed, 15 Jun 2016 18:11:33 -0700 [thread overview]
Message-ID: <5761FCC5.3010709@codeaurora.org> (raw)
In-Reply-To: <1465844571-1229-1-git-send-email-bjorn.andersson@linaro.org>
On 06/13/2016 12:02 PM, Bjorn Andersson wrote:
> Upon opening the tty, uart_open() ends up calling msm_set_baud_rate()
> which resets the uart block. If this happens as we're coming out of
> msm_console_write() a full fifo worth of console output will be
> discarded.
>
> Cc: Stephen Boyd <sboyd@codeaurora.org>
> Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
> ---
>
> As reported here:
> https://bugs.96boards.org/show_bug.cgi?id=378
Urgh. As mentioned in commit a12f1b406f2d (tty: serial: msm: Reset
uartdm after baud rate change, 2014-10-29) we actually need to reset the
hardware sometimes. Perhaps as discussed over IRC we need to take a
different approach here and only reset the hardware if the baud actually
changes? One way to test this would be to try running a getty on the
console and see if input still works.
--
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
a Linux Foundation Collaborative Project
next prev parent reply other threads:[~2016-06-16 1:11 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-13 19:02 [RFC PATCH] tty: serial: msm_serial: Don't reset uart on set_termios Bjorn Andersson
2016-06-15 12:58 ` Pramod Gurav
2016-06-16 1:11 ` Stephen Boyd [this message]
2016-06-16 18:24 ` [PATCH v2] tty: serial: msm: Don't reconfigure same baud rate Bjorn Andersson
2016-06-17 10:02 ` Nicolas Dechesne
2016-06-21 9:43 ` Nicolas Dechesne
2016-06-22 9:59 ` Srinivas Kandagatla
2016-06-20 23:54 ` Stephen Boyd
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