Merge tag 'tty-6.10-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty

Pull tty / serial updates from Greg KH:
 "Here is the big set of tty/serial driver changes for 6.10-rc1.
  Included in here are:

   - Usual good set of api cleanups and evolution by Jiri Slaby to make
     the serial interfaces move out of the 1990's by using kfifos
     instead of hand-rolling their own logic.

   - 8250_exar driver updates

   - max3100 driver updates

   - sc16is7xx driver updates

   - exar driver updates

   - sh-sci driver updates

   - tty ldisc api addition to help refuse bindings

   - other smaller serial driver updates

  All of these have been in linux-next for a while with no reported
  issues"

* tag 'tty-6.10-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: (113 commits)
  serial: Clear UPF_DEAD before calling tty_port_register_device_attr_serdev()
  serial: imx: Raise TX trigger level to 8
  serial: 8250_pnp: Simplify "line" related code
  serial: sh-sci: simplify locking when re-issuing RXDMA fails
  serial: sh-sci: let timeout timer only run when DMA is scheduled
  serial: sh-sci: describe locking requirements for invalidating RXDMA
  serial: sh-sci: protect invalidating RXDMA on shutdown
  tty: add the option to have a tty reject a new ldisc
  serial: core: Call device_set_awake_path() for console port
  dt-bindings: serial: brcm,bcm2835-aux-uart: convert to dtschema
  tty: serial: uartps: Add support for uartps controller reset
  arm64: zynqmp: Add resets property for UART nodes
  dt-bindings: serial: cdns,uart: Add optional reset property
  serial: 8250_pnp: Switch to DEFINE_SIMPLE_DEV_PM_OPS()
  serial: 8250_exar: Keep the includes sorted
  serial: 8250_exar: Make type of bit the same in exar_ee_*_bit()
  serial: 8250_exar: Use BIT() in exar_ee_read()
  serial: 8250_exar: Switch to use dev_err_probe()
  serial: 8250_exar: Return directly from switch-cases
  serial: 8250_exar: Decrease indentation level
  ...

2 files changed, 28 insertions, 0 deletions

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index ef25e06ec08c..500cfa776225 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -788,6 +788,25 @@
 			Documentation/networking/netconsole.rst for an
 			alternative.
 
+		<DEVNAME>:<n>.<n>[,options]
+			Use the specified serial port on the serial core bus.
+			The addressing uses DEVNAME of the physical serial port
+			device, followed by the serial core controller instance,
+			and the serial port instance. The options are the same
+			as documented for the ttyS addressing above.
+
+			The mapping of the serial ports to the tty instances
+			can be viewed with:
+
+			$ ls -d /sys/bus/serial-base/devices/*:*.*/tty/*
+			/sys/bus/serial-base/devices/00:04:0.0/tty/ttyS0
+
+			In the above example, the console can be addressed with
+			console=00:04:0.0. Note that a console addressed this
+			way will only get added when the related device driver
+			is ready. The use of an earlycon parameter in addition to
+			the console may be desired for console output early on.
+
 		uart[8250],io,<addr>[,options]
 		uart[8250],mmio,<addr>[,options]
 		uart[8250],mmio16,<addr>[,options]
diff --git a/Documentation/admin-guide/sysrq.rst b/Documentation/admin-guide/sysrq.rst
index 2f2e5bd440f9..a85b3384d1e7 100644
--- a/Documentation/admin-guide/sysrq.rst
+++ b/Documentation/admin-guide/sysrq.rst
@@ -161,6 +161,8 @@ Command	    Function
             will be printed to your console. (``0``, for example would make
             it so that only emergency messages like PANICs or OOPSes would
             make it to your console.)
+
+``R``	    Replay the kernel log messages on consoles.
 =========== ===================================================================
 
 Okay, so what can I use them for?
@@ -211,6 +213,13 @@ processes.
 "just thaw ``it(j)``" is useful if your system becomes unresponsive due to a
 frozen (probably root) filesystem via the FIFREEZE ioctl.
 
+``Replay logs(R)`` is useful to view the kernel log messages when system is hung
+or you are not able to use dmesg command to view the messages in printk buffer.
+User may have to press the key combination multiple times if console system is
+busy. If it is completely locked up, then messages won't be printed. Output
+messages depend on current console loglevel, which can be modified using
+sysrq[0-9] (see above).
+
 Sometimes SysRq seems to get 'stuck' after using it, what can I do?
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~