linux-kernel - [RESEND PATCH 0/2] tty: serial: Fix kgdb on qcom-geni-serial when no other UART users

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Date:   Thu, 16 Mar 2023 13:20:55 -0700
From:   Douglas Anderson <dianders@...omium.org>
To:     Bjorn Andersson <andersson@...nel.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc:     linux-arm-msm@...r.kernel.org, Jiri Slaby <jirislaby@...nel.org>,
        Bartosz Golaszewski <bartosz.golaszewski@...aro.org>,
        Daniel Thompson <daniel.thompson@...aro.org>,
        kgdb-bugreport@...ts.sourceforge.net,
        Konrad Dybcio <konrad.dybcio@...aro.org>,
        linux-serial@...r.kernel.org,
        Douglas Anderson <dianders@...omium.org>,
        Andy Gross <agross@...nel.org>, linux-kernel@...r.kernel.org
Subject: [RESEND PATCH 0/2] tty: serial: Fix kgdb on qcom-geni-serial when no other UART users

Today to get kgdb to work on qcom-geni-serial devices you need
_something_ to init/power on the UART. This could either the kernel
console output or an "agetty" running on the port. If nothing else
powers the port then you'll end up getting a silent hang when you try
to enter kgdb.

Let's fix this. The first patch here is for the tty layer to make sure
that we power on the port when we init it for polling. This would be
important for any drivers similar to qcom-geni-serial that actually
need to be powered on. The second patch here hooks up the poll_init()
function for qcom-geni-serial, leveraging an existing function in the
driver that does everything we need.

Originally these two patches were bundled together as pathes 2 and 3
of a 3-patch series.  We no longer need the first patch from the
orginal series since we landed a similar patch from Johan [1]
instead. The second two patches are still useful, though, so I've
reposted them alone and added this cover letter.

[1] https://lore.kernel.org/r/20230307164405.14218-1-johan+linaro@kernel.org

Douglas Anderson (2):
  serial: uart_poll_init() should power on the UART
  tty: serial: qcom-geni-serial: Add a poll_init() function

 drivers/tty/serial/qcom_geni_serial.c | 1 +
 drivers/tty/serial/serial_core.c      | 6 ++++++
 2 files changed, 7 insertions(+)

-- 
2.40.0.rc1.284.g88254d51c5-goog