diff mbox series

[v10,15/69] drm/bridge: Add bridge ops for source-side HDMI 2.0 scrambling

Message ID 20260731-dw-hdmi-qp-scramb-v10-15-294364b2cf15@collabora.com (mailing list archive)
State New
Headers
Series Add HDMI 2.0 support to DW HDMI QP TX |

Commit Message

Cristian Ciocaltea July 31, 2026, 4:19 p.m. UTC 
Bridges advertising HDMI 2.0 must be able to enable and disable
source-side scrambling and the high TMDS clock ratio when the configured
mode exceeds 340 MHz.

Add .hdmi_scrambler_{enable|disable}() callbacks covering the
source-side programming only; sink-side SCDC negotiation remains the job
of the HDMI connector helpers.

Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
Signed-off-by: Cristian Ciocaltea <cristian.ciocaltea@collabora.com>
---
 include/drm/drm_bridge.h | 35 +++++++++++++++++++++++++++++++++++
 1 file changed, 35 insertions(+)

Comments

sashiko-bot@kernel.org July 31, 2026, 6:09 p.m. UTC | #1 
Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Medium] Missing API implementation for bridge HDMI 2.0 scrambler callbacks causes unconditional probe failure.
--

--- Patch [15]: [PATCH v10 15/69] drm/bridge: Add bridge ops for source-side HDMI 2.0 scrambling ---
commit 5577332c0f45e627e54f1e2997be97e38fdecf40
Author: Cristian Ciocaltea <cristian.ciocaltea@collabora.com>

drm/bridge: Add bridge ops for source-side HDMI 2.0 scrambling

This commit adds hdmi_scrambler_enable() and hdmi_scrambler_disable()
callbacks to struct drm_bridge_funcs. These allow bridges to enable or
disable source-side scrambling and high TMDS clock ratios for modes
exceeding 340 MHz.

> diff --git a/include/drm/drm_bridge.h b/include/drm/drm_bridge.h
> index 5a5a25995471c..77b3ffe692304 100644
> --- a/include/drm/drm_bridge.h
> +++ b/include/drm/drm_bridge.h
[ ... ]
> +	/**
> +	 * @hdmi_scrambler_enable:
> +	 *
> +	 * Enable source-side scrambling and the high TMDS clock ratio for the
> +	 * mode currently being applied.
[ ... ]
> +	 * Returns:
> +	 * 0 on success, a negative error code otherwise.
> +	 */
> +	int (*hdmi_scrambler_enable)(struct drm_bridge *bridge);
> +
> +	/**
> +	 * @hdmi_scrambler_disable:
> +	 *
> +	 * Disable source-side scrambling and the high TMDS clock ratio.
[ ... ]
> +	 * Returns:
> +	 * 0 on success, a negative error code otherwise.
> +	 */
> +	int (*hdmi_scrambler_disable)(struct drm_bridge *bridge);

[Severity: Medium]
Are these newly added callbacks being hooked up to the DRM connector
infrastructure?

Looking at drm_bridge_connector_init() in drm_bridge_connector.c, it
initializes hdmi_funcs but doesn't seem to map these new bridge callbacks:

		bridge_connector->hdmi_funcs = drm_bridge_connector_hdmi_funcs;

		bridge_connector->hdmi_funcs.vendor = bridge_connector->bridge_hdmi->vendor;
		bridge_connector->hdmi_funcs.product = bridge_connector->bridge_hdmi->product;

If a bridge advertises HDMI_VERSION_2_0, will drmm_connector_hdmi_init()
fail with -EINVAL during probe because the connector's hdmi_funcs are
missing these required scrambler callbacks?
diff mbox series

Patch

diff --git a/include/drm/drm_bridge.h b/include/drm/drm_bridge.h
index 5a5a25995471..77b3ffe69230 100644
--- a/include/drm/drm_bridge.h
+++ b/include/drm/drm_bridge.h
@@ -561,6 +561,41 @@  struct drm_bridge_funcs {
 				     const struct drm_display_mode *mode,
 				     unsigned long long tmds_rate);
 
+	/**
+	 * @hdmi_scrambler_enable:
+	 *
+	 * Enable source-side scrambling and the high TMDS clock ratio for the
+	 * mode currently being applied.
+	 *
+	 * This only programs the source side. Sink-side SCDC configuration is
+	 * handled by the HDMI connector helpers.
+	 *
+	 * Mandatory for bridges that set the DRM_BRIDGE_OP_HDMI flag in their
+	 * &drm_bridge->ops and advertise HDMI_VERSION_2_0 or later via
+	 * &drm_bridge->supported_hdmi_ver; unused otherwise.
+	 *
+	 * Returns:
+	 * 0 on success, a negative error code otherwise.
+	 */
+	int (*hdmi_scrambler_enable)(struct drm_bridge *bridge);
+
+	/**
+	 * @hdmi_scrambler_disable:
+	 *
+	 * Disable source-side scrambling and the high TMDS clock ratio.
+	 *
+	 * This only programs the source side. Sink-side SCDC configuration is
+	 * handled by the HDMI connector helpers.
+	 *
+	 * Mandatory for bridges that set the DRM_BRIDGE_OP_HDMI flag in their
+	 * &drm_bridge->ops and advertise HDMI_VERSION_2_0 or later via
+	 * &drm_bridge->supported_hdmi_ver; unused otherwise.
+	 *
+	 * Returns:
+	 * 0 on success, a negative error code otherwise.
+	 */
+	int (*hdmi_scrambler_disable)(struct drm_bridge *bridge);
+
 	/**
 	 * @hdmi_clear_avi_infoframe:
 	 *