The recently added pcm-test selftest has pointed out that systems with the tda998x driver end up advertising that they support capture when in reality as far as I can see the tda998x devices are transmit only. The DAIs registered through hdmi-codec are bidirectional, meaning that for I2S systems when combined with a typical bidrectional CPU DAI the overall capability of the PCM is bidirectional. In most cases the I2S links will clock OK but no useful audio will be returned which isn't so bad but we should still not advertise the useless capability, and some systems may notice problems for example due to pinmux management.
This is happening due to the hdmi-codec helpers not providing any mechanism for indicating unidirectional audio so add one and use it in the tda998x driver. It is likely other hdmi-codec users are also affected but I don't have those systems to hand.
Mark Brown (2): ASoC: hdmi-codec: Allow playback and capture to be disabled drm: tda99x: Don't advertise non-existent capture support
drivers/gpu/drm/i2c/tda998x_drv.c | 2 ++ include/sound/hdmi-codec.h | 4 ++++ sound/soc/codecs/hdmi-codec.c | 30 +++++++++++++++++++++++++----- 3 files changed, 31 insertions(+), 5 deletions(-)
base-commit: f0c4d9fc9cc9462659728d168387191387e903cc