[PATCH v2 0/7] Improve latency of IR decoding

Sean Young sean at mess.org
Sun Apr 8 14:19:35 PDT 2018


The current IR decoding is much too slow. Many IR protocols rely on
a trailing space for decoding (e.g. rc-6 needs to know when the bits
end). The trailing space is generated by the IR timeout, and if this
is longer than required, buttons can feel slow to respond.

The other issue is the keyup timer. IR has no concept of a keyup message,
this is implied by the absence of IR. So, minimising the timeout for
this makes buttons less "sticky"; the are released much quicker.

With these patches in place, using IR with the builtin decoders is much
improved and feels very snappy.

Changes since v1:
 - lost more testing
 - fixed various issues with mce decoder
 - fixed mceusb so it can use better timeout too

Sean Young (7):
  media: rc: set timeout to smallest value required by enabled protocols
  media: rc: add ioctl to get the current timeout
  media: rc: per-protocol repeat period and minimum keyup timer
  media: rc: mce_kbd decoder: low timeout values cause double keydowns
  media: rc: mce_kbd protocol encodes two scancodes
  media: rc: mce_kbd decoder: fix stuck keys
  media: rc: mceusb: allow the timeout to be configurable

 Documentation/media/uapi/rc/lirc-func.rst          |  1 +
 .../media/uapi/rc/lirc-set-rec-timeout.rst         | 14 +++--
 drivers/media/cec/cec-core.c                       |  2 +-
 drivers/media/rc/ir-imon-decoder.c                 |  1 +
 drivers/media/rc/ir-jvc-decoder.c                  |  1 +
 drivers/media/rc/ir-mce_kbd-decoder.c              | 36 +++++++-----
 drivers/media/rc/ir-nec-decoder.c                  |  1 +
 drivers/media/rc/ir-rc5-decoder.c                  |  1 +
 drivers/media/rc/ir-rc6-decoder.c                  |  1 +
 drivers/media/rc/ir-sanyo-decoder.c                |  1 +
 drivers/media/rc/ir-sharp-decoder.c                |  1 +
 drivers/media/rc/ir-sony-decoder.c                 |  1 +
 drivers/media/rc/ir-xmp-decoder.c                  |  1 +
 drivers/media/rc/lirc_dev.c                        |  9 ++-
 drivers/media/rc/mceusb.c                          | 22 +++++++
 drivers/media/rc/rc-core-priv.h                    |  1 +
 drivers/media/rc/rc-ir-raw.c                       | 31 +++++++++-
 drivers/media/rc/rc-main.c                         | 68 +++++++++++-----------
 include/uapi/linux/lirc.h                          |  6 ++
 19 files changed, 144 insertions(+), 55 deletions(-)

-- 
2.14.3




More information about the linux-amlogic mailing list