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[dann frazier <dann.frazier@xxxxxxxxxxxxx>]

Public bug reported:

HP Moonshot cartridges support hardware flow control, but right now only
software assisted hw flow control is supported. This patch from upstream
enables this functionality when exposed by firmware:

commit 06aa82e498c144c7784a6f3d3b55458b272d6146
Author: Murali Karicheri <m-karicheri2@xxxxxx>
Date:   Thu May 1 15:04:53 2014 -0400

    serial: uart: add hw flow control support configuration
    
    8250 uart driver currently supports only software assisted hw flow
    control. The software assisted hw flow control maintains a hw_stopped
    flag in the tty structure to stop and start transmission and use modem
    status interrupt for the event to drive the handshake signals. This is
    not needed if hw has flow control capabilities. This patch adds a
    DT attribute for enabling hw flow control for a uart port. Also skip
    stop and start if this flag is present in flag field of the port
    structure.
    
    Signed-off-by: Murali Karicheri <m-karicheri2@xxxxxx>
    CC: Rob Herring <robh+dt@xxxxxxxxxx>
    CC: Pawel Moll <pawel.moll@xxxxxxx>
    CC: Mark Rutland <mark.rutland@xxxxxxx>
    CC: Ian Campbell <ijc+devicetree@xxxxxxxxxxxxxx>
    CC: Kumar Gala <galak@xxxxxxxxxxxxxx>
    CC: Randy Dunlap <rdunlap@xxxxxxxxxxxxx>
    CC: Jiri Slaby <jslaby@xxxxxxx>
    CC: Santosh Shilimkar <santosh.shilimkar@xxxxxx>
    Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

** Affects: linux (Ubuntu)
     Importance: Undecided
         Status: New


** Tags: hs-arm64

** Attachment added: "0001-serial-uart-add-hw-flow-control-support-configuratio.patch"
   https://bugs.launchpad.net/bugs/1328295/+attachment/4128491/+files/0001-serial-uart-add-hw-flow-control-support-configuratio.patch

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https://bugs.launchpad.net/bugs/1328295

Title:
  [serial] use hw flow control if supported

Status in “linux” package in Ubuntu:
  New

Bug description:
  HP Moonshot cartridges support hardware flow control, but right now
  only software assisted hw flow control is supported. This patch from
  upstream enables this functionality when exposed by firmware:

  commit 06aa82e498c144c7784a6f3d3b55458b272d6146
  Author: Murali Karicheri <m-karicheri2@xxxxxx>
  Date:   Thu May 1 15:04:53 2014 -0400

      serial: uart: add hw flow control support configuration
      
      8250 uart driver currently supports only software assisted hw flow
      control. The software assisted hw flow control maintains a hw_stopped
      flag in the tty structure to stop and start transmission and use modem
      status interrupt for the event to drive the handshake signals. This is
      not needed if hw has flow control capabilities. This patch adds a
      DT attribute for enabling hw flow control for a uart port. Also skip
      stop and start if this flag is present in flag field of the port
      structure.
      
      Signed-off-by: Murali Karicheri <m-karicheri2@xxxxxx>
      CC: Rob Herring <robh+dt@xxxxxxxxxx>
      CC: Pawel Moll <pawel.moll@xxxxxxx>
      CC: Mark Rutland <mark.rutland@xxxxxxx>
      CC: Ian Campbell <ijc+devicetree@xxxxxxxxxxxxxx>
      CC: Kumar Gala <galak@xxxxxxxxxxxxxx>
      CC: Randy Dunlap <rdunlap@xxxxxxxxxxxxx>
      CC: Jiri Slaby <jslaby@xxxxxxx>
      CC: Santosh Shilimkar <santosh.shilimkar@xxxxxx>
      Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

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