[PATCH 0/3] Improve dw-hdmi CTS/N setting

Russell King - ARM Linux linux at arm.linux.org.uk
Fri Mar 27 04:13:20 PDT 2015


This is a mini-series to try and move audio support for the Designware
HDMI bridge along.

There are two known versions of the Designware HDMI audio:

- The Rockchip version, which is based upon feeding the HDMI block I2S
  stream(s), which doesn't have any on-board DMA support.
- The Freescale version, which only has AHB DMA support.

There are two drivers around at present, one which I've had which is
ALSA based due to its simplicity for the Freescale version of the IP,
and one which is ASoC based from Yakir Yang for the Rockchip version.

There is some commonality between the two drivers - for example, the
setup of the CTS/N values is very similar, although not identical.

I have been reviewing (when time permits) the patches from Yakir Yang,
and making recommendations to try and extract the common parts of the
driver.  This is the patch set I came up with (mentioned in
20150202130920.GC8656 at n2100.arm.linux.org.uk).

Yakir merged some of my ideas into his patch set - for example, Yakir
Yang's "drm: bridge/dw_hdmi: combine hdmi_set_clock_regenerator_n() and
hdmi_regenerate_cts()" is very close to the version which I came up

Yakir Yang didn't include the mutex patch, which I've included here -
it really is necessary because we have potentially two different
threads which can change the CTS/N values - a change of the video mode
vs a change in the audio driver.

The last patch is adjusting the CTS/N setting order - I have only gone
as far as what we know works for iMX6, and this is also identical to
Yakir Yang's patch.

The identical nature is hardly surprising; my patches were derived from
a previous set of his patches (which I acknowledge in the commit messages)
and I detailed in the above message what I wanted to see.

What I would like to see is that - as we are effectively in agreement
over two of these patches - we get these patches merged rather than
having to repeatedly see them.  If there's any objection, please let me
know, otherwise I'll collect acks and send them to David.

 drivers/gpu/drm/bridge/dw_hdmi.c | 34 +++++++++++++++++++---------------
 1 file changed, 19 insertions(+), 15 deletions(-)

FTTC broadband for 0.8mile line: currently at 10.5Mbps down 400kbps up
according to speedtest.net.

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