Hi,
On 30/10/2025 17:16, Devarsh Thakkar wrote:
> The sii902x driver was caching HDMI detection state in a sink_is_hdmi field
> and checking it in mode_set() to determine whether to set HDMI or DVI
> output mode. This approach had two problems:
>
> 1. With DRM_BRIDGE_ATTACH_NO_CONNECTOR (used by modern display drivers like
> TIDSS), the bridge's get_modes() is never called. Instead, the
> drm_bridge_connector helper calls the bridge's edid_read() and updates the
> connector itself. This meant sink_is_hdmi was never populated, causing the
> driver to default to DVI mode and breaking HDMI audio.
>
> 2. The mode_set() callback doesn't receive atomic state or connector
> pointer, making it impossible to check connector->display_info.is_hdmi
> directly at that point.
>
> Fix this by moving the HDMI vs DVI decision from mode_set() to
> atomic_enable(), where we can access the connector via
> drm_atomic_get_new_connector_for_encoder(). This works for both connector
> models:
>
> - With DRM_BRIDGE_ATTACH_NO_CONNECTOR: Returns the drm_bridge_connector
> created by the display driver, which has already been updated by the
> helper's call to drm_edid_connector_update()
>
> - Without DRM_BRIDGE_ATTACH_NO_CONNECTOR (legacy): Returns the connector
> embedded in sii902x struct, which gets updated by the bridge's own
> get_modes()
>
> Fixes: 3de47e1309c2 ("drm/bridge: sii902x: use display info is_hdmi")
> Signed-off-by: Devarsh Thakkar <[email protected]>
> ---
> V4: Shift HDMI detection to atomic_enable() and remove sink_is_hdmi caching
> V3: Use drm_edid_connector_update without edid NULL check
> V2: Use drm_edid_connector_update to detect HDMI
>
> Link to V3:
> https://lore.kernel.org/all/[email protected]/
> Link to V2:
> https://lore.kernel.org/all/[email protected]/
> Link to V1:
> https://lore.kernel.org/all/[email protected]/
>
> drivers/gpu/drm/bridge/sii902x.c | 20 ++++++++------------
> 1 file changed, 8 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/gpu/drm/bridge/sii902x.c
> b/drivers/gpu/drm/bridge/sii902x.c
> index d537b1d036fb..1f0aba28ad1e 100644
> --- a/drivers/gpu/drm/bridge/sii902x.c
> +++ b/drivers/gpu/drm/bridge/sii902x.c
> @@ -179,7 +179,6 @@ struct sii902x {
> struct drm_connector connector;
> struct gpio_desc *reset_gpio;
> struct i2c_mux_core *i2cmux;
> - bool sink_is_hdmi;
> u32 bus_width;
>
> /*
> @@ -315,8 +314,6 @@ static int sii902x_get_modes(struct drm_connector
> *connector)
> drm_edid_free(drm_edid);
> }
>
> - sii902x->sink_is_hdmi = connector->display_info.is_hdmi;
> -
> return num;
> }
>
> @@ -342,9 +339,17 @@ static void sii902x_bridge_atomic_enable(struct
> drm_bridge *bridge,
> struct drm_atomic_state *state)
> {
> struct sii902x *sii902x = bridge_to_sii902x(bridge);
> + struct drm_connector *connector;
> + u8 output_mode = SII902X_SYS_CTRL_OUTPUT_DVI;
> +
> + connector = drm_atomic_get_new_connector_for_encoder(state,
> bridge->encoder);
> + if (connector && connector->display_info.is_hdmi)
> + output_mode = SII902X_SYS_CTRL_OUTPUT_HDMI;
>
> mutex_lock(&sii902x->mutex);
>
> + regmap_update_bits(sii902x->regmap, SII902X_SYS_CTRL_DATA,
> + SII902X_SYS_CTRL_OUTPUT_MODE, output_mode);
> regmap_update_bits(sii902x->regmap, SII902X_PWR_STATE_CTRL,
> SII902X_AVI_POWER_STATE_MSK,
> SII902X_AVI_POWER_STATE_D(0));
> @@ -359,16 +364,12 @@ static void sii902x_bridge_mode_set(struct drm_bridge
> *bridge,
> const struct drm_display_mode *adj)
> {
> struct sii902x *sii902x = bridge_to_sii902x(bridge);
> - u8 output_mode = SII902X_SYS_CTRL_OUTPUT_DVI;
> struct regmap *regmap = sii902x->regmap;
> u8 buf[HDMI_INFOFRAME_SIZE(AVI)];
> struct hdmi_avi_infoframe frame;
> u16 pixel_clock_10kHz = adj->clock / 10;
> int ret;
>
> - if (sii902x->sink_is_hdmi)
> - output_mode = SII902X_SYS_CTRL_OUTPUT_HDMI;
> -
> buf[0] = pixel_clock_10kHz & 0xff;
> buf[1] = pixel_clock_10kHz >> 8;
> buf[2] = drm_mode_vrefresh(adj);
> @@ -384,11 +385,6 @@ static void sii902x_bridge_mode_set(struct drm_bridge
> *bridge,
>
> mutex_lock(&sii902x->mutex);
>
> - ret = regmap_update_bits(sii902x->regmap, SII902X_SYS_CTRL_DATA,
> - SII902X_SYS_CTRL_OUTPUT_MODE, output_mode);
> - if (ret)
> - goto out;
> -
> ret = regmap_bulk_write(regmap, SII902X_TPI_VIDEO_DATA, buf, 10);
> if (ret)
> goto out;
Reviewed-by: Tomi Valkeinen <[email protected]>
Tomi
