Hi,
On Wed, Aug 28, 2019 at 9:30 PM Cheng-Yi Chiang cychiang@chromium.org wrote:
In the designware databook, the sequence of enabling audio clock and setting format is not clearly specified. Currently, audio clock is enabled in the end of hw_param ops after setting format.
On some monitors, there is a possibility that audio does not come out. Fix this by enabling audio clock in audio_startup ops before hw_param ops setting format.
Signed-off-by: Cheng-Yi Chiang cychiang@chromium.org
drivers/gpu/drm/bridge/synopsys/dw-hdmi-i2s-audio.c | 9 +++++++++ 1 file changed, 9 insertions(+)
diff --git a/drivers/gpu/drm/bridge/synopsys/dw-hdmi-i2s-audio.c b/drivers/gpu/drm/bridge/synopsys/dw-hdmi-i2s-audio.c index 5cbb71a866d5..08b4adbb1ddc 100644 --- a/drivers/gpu/drm/bridge/synopsys/dw-hdmi-i2s-audio.c +++ b/drivers/gpu/drm/bridge/synopsys/dw-hdmi-i2s-audio.c @@ -69,6 +69,14 @@ static int dw_hdmi_i2s_hw_params(struct device *dev, void *data, hdmi_write(audio, conf0, HDMI_AUD_CONF0); hdmi_write(audio, conf1, HDMI_AUD_CONF1);
return 0;+}
+static int dw_hdmi_i2s_audio_startup(struct device *dev, void *data) +{
struct dw_hdmi_i2s_audio_data *audio = data;struct dw_hdmi *hdmi = audio->hdmi;dw_hdmi_audio_enable(hdmi); return 0;@@ -105,6 +113,7 @@ static int dw_hdmi_i2s_get_dai_id(struct snd_soc_component *component, }
static struct hdmi_codec_ops dw_hdmi_i2s_ops = {
.audio_startup = dw_hdmi_i2s_audio_startup, .hw_params = dw_hdmi_i2s_hw_params, .audio_shutdown = dw_hdmi_i2s_audio_shutdown, .get_dai_id = dw_hdmi_i2s_get_dai_id,--
I am no expert on audio stuff, but this seems sane to me. If you happened to spin it for another reason, it might seem slightly nicer to put the setting of ".audio_startup" adjacent to the setting of ".audio_shutdown" in the struct.
I have tested your patch on Chrome OS 4.19 and it definitely fixes the problems I saw. Chrome OS 4.19 is a little different than upstream and I'm not setup to test HDMI audio directly on upstream, but I did at least confirm that my problem _wasn't_ magically fixed by any of these patches that I found upstream (I picked them into my tree and still saw the problem):
fc1ca6e01d0a drm/bridge: dw-hdmi-i2s: add .get_eld support 43e88f670a5e drm/bridge: dw-hdmi-i2s: enable only the required i2s lanes 46cecde310bb drm/bridge: dw-hdmi-i2s: reset audio fifo before applying new params 0c6098859176 drm/bridge: dw-hdmi-i2s: set the channel allocation 17a1e555b608 drm/bridge: dw-hdmi-i2s: enable lpcm multi channels da5f5bc92f49 drm/bridge: dw-hdmi: set channel count in the infoframes 2a2a3d2ff799 drm/bridge: dw-hdmi: move audio channel setup out of ahb 8067f62bccaf drm/bridge: dw-hdmi-i2s: support more i2s format
Thus:
Reviewed-by: Douglas Anderson dianders@chromium.org Tested-by: Douglas Anderson dianders@chromium.org
-Doug