[PATCH v3] drm/bridge: dw-hdmi: Restore audio when setting a mode

From: Cheng-Yi Chiang
Date: Tue Oct 08 2019 - 06:21:55 EST

From: Daniel Kurtz <djkurtz@xxxxxxxxxxxx>

When setting a new display mode, dw_hdmi_setup() calls
dw_hdmi_enable_video_path(), which disables all hdmi clocks, including
the audio clock.

We should only (re-)enable the audio clock if audio was already enabled
when setting the new mode.

Without this patch, on RK3288, there will be HDMI audio on some monitors
if i2s was played to headphone when the monitor was plugged.
ACER H277HU and ASUS PB278 are two of the monitors showing this issue.

Signed-off-by: Cheng-Yi Chiang <cychiang@xxxxxxxxxxxx>
Signed-off-by: Daniel Kurtz <djkurtz@xxxxxxxxxxxx>
Signed-off-by: Yakir Yang <ykk@xxxxxxxxxxxxxx>
Change from v2 to v3:
- Remove spinlock around setting clock.

drivers/gpu/drm/bridge/synopsys/dw-hdmi.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c b/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
index a15fbf71b9d7..af060162b0af 100644
--- a/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
+++ b/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
@@ -2054,7 +2054,7 @@ static int dw_hdmi_setup(struct dw_hdmi *hdmi, struct drm_display_mode *mode)

/* HDMI Initialization Step E - Configure audio */
- hdmi_enable_audio_clk(hdmi, true);
+ hdmi_enable_audio_clk(hdmi, hdmi->audio_enable);

/* not for DVI mode */