On Fri, Jul 31, 2026 at 07:19:52PM +0300, Cristian Ciocaltea wrote:
> Replace driver local scrambling logic with the newly introduced common
> HDMI 2.0 scrambling support:
>
> - Advertise source-side scrambling capability by setting supported HDMI
> version based on the variant's max_pixel_clock.
>
> - Provide minimal .scrambler_{enable,disable} connector callbacks that
> only toggle the VC5 HDMI_SCRAMBLER_CTL register, while delegating
> sink-side SCDC programming and periodic status monitoring to
> drm_connector_hdmi_{enable,disable}_scrambling().
>
> - Drop vc4_hdmi_reset_link() and vc4_hdmi_handle_hotplug(), switching
> the .detect_ctx() path to drm_atomic_helper_connector_hdmi_hotplug()
> which internally calls drm_connector_hdmi_sync_scdc() to trigger a
> CRTC reset on reconnection.
>
> - Drop the local scrambling_work delayed workqueue and scdc_enabled
> flag, now tracked by the common drm_connector_hdmi layer, as well as
> the now unused output_{bpc,color_format} driver data members.
>
> No functional change intended.
>
> Signed-off-by: Cristian Ciocaltea <[email protected]>
> ---
> drivers/gpu/drm/vc4/vc4_hdmi.c | 230
> +++++------------------------------------
> drivers/gpu/drm/vc4/vc4_hdmi.h | 21 ----
> 2 files changed, 28 insertions(+), 223 deletions(-)
>
> diff --git a/drivers/gpu/drm/vc4/vc4_hdmi.c b/drivers/gpu/drm/vc4/vc4_hdmi.c
> index d599957fee3a..ec0c1f4224d7 100644
> --- a/drivers/gpu/drm/vc4/vc4_hdmi.c
> +++ b/drivers/gpu/drm/vc4/vc4_hdmi.c
> @@ -35,7 +35,6 @@
> #include <drm/display/drm_hdmi_cec_helper.h>
> #include <drm/display/drm_hdmi_helper.h>
> #include <drm/display/drm_hdmi_state_helper.h>
> -#include <drm/display/drm_scdc_helper.h>
> #include <drm/drm_atomic_helper.h>
> #include <drm/drm_drv.h>
> #include <drm/drm_edid.h>
> @@ -114,22 +113,6 @@
> #define HSM_MIN_CLOCK_FREQ 120000000
> #define CEC_CLOCK_FREQ 40000
>
> -static bool vc4_hdmi_supports_scrambling(struct vc4_hdmi *vc4_hdmi)
> -{
> - struct drm_display_info *display = &vc4_hdmi->connector.display_info;
> -
> - lockdep_assert_held(&vc4_hdmi->mutex);
> -
> - if (!display->is_hdmi)
> - return false;
> -
> - if (!display->hdmi.scdc.supported ||
> - !display->hdmi.scdc.scrambling.supported)
> - return false;
> -
> - return true;
> -}
> -
> static int vc4_hdmi_debugfs_regs(struct seq_file *m, void *unused)
> {
> struct drm_debugfs_entry *entry = m->private;
> @@ -263,115 +246,6 @@ static void vc4_hdmi_cec_update_clk_div(struct vc4_hdmi
> *vc4_hdmi)
> static void vc4_hdmi_cec_update_clk_div(struct vc4_hdmi *vc4_hdmi) {}
> #endif
>
> -static int vc4_hdmi_reset_link(struct drm_connector *connector,
> - struct drm_modeset_acquire_ctx *ctx)
> -{
> - struct drm_device *drm;
> - struct vc4_hdmi *vc4_hdmi;
> - struct drm_connector_state *conn_state;
> - struct drm_crtc_state *crtc_state;
> - struct drm_crtc *crtc;
> - bool scrambling_needed;
> - u8 config;
> - int ret;
> -
> - if (!connector)
> - return 0;
> -
> - drm = connector->dev;
> - ret = drm_modeset_lock(&drm->mode_config.connection_mutex, ctx);
> - if (ret)
> - return ret;
> -
> - conn_state = connector->state;
> - crtc = conn_state->crtc;
> - if (!crtc)
> - return 0;
> -
> - ret = drm_modeset_lock(&crtc->mutex, ctx);
> - if (ret)
> - return ret;
> -
> - crtc_state = crtc->state;
> - if (!crtc_state->active)
> - return 0;
> -
> - vc4_hdmi = connector_to_vc4_hdmi(connector);
> - mutex_lock(&vc4_hdmi->mutex);
> -
> - if (!vc4_hdmi_supports_scrambling(vc4_hdmi)) {
> - mutex_unlock(&vc4_hdmi->mutex);
> - return 0;
> - }
> -
> - scrambling_needed =
> drm_hdmi_mode_needs_scrambling(&vc4_hdmi->saved_adjusted_mode,
> - vc4_hdmi->output_bpc,
> -
> vc4_hdmi->output_format);
> - if (!scrambling_needed) {
> - mutex_unlock(&vc4_hdmi->mutex);
> - return 0;
> - }
> -
> - if (conn_state->commit &&
> - !try_wait_for_completion(&conn_state->commit->hw_done)) {
> - mutex_unlock(&vc4_hdmi->mutex);
> - return 0;
> - }
> -
> - ret = drm_scdc_readb(connector->ddc, SCDC_TMDS_CONFIG, &config);
> - if (ret < 0) {
> - drm_err(drm, "Failed to read TMDS config: %d\n", ret);
> - mutex_unlock(&vc4_hdmi->mutex);
> - return 0;
> - }
> -
> - if (!!(config & SCDC_SCRAMBLING_ENABLE) == scrambling_needed) {
> - mutex_unlock(&vc4_hdmi->mutex);
> - return 0;
> - }
> -
> - mutex_unlock(&vc4_hdmi->mutex);
> -
> - /*
> - * HDMI 2.0 says that one should not send scrambled data
> - * prior to configuring the sink scrambling, and that
> - * TMDS clock/data transmission should be suspended when
> - * changing the TMDS clock rate in the sink. So let's
> - * just do a full modeset here, even though some sinks
> - * would be perfectly happy if were to just reconfigure
> - * the SCDC settings on the fly.
> - */
> - return drm_atomic_helper_reset_crtc(crtc, ctx);
> -}
> -
> -static int vc4_hdmi_handle_hotplug(struct vc4_hdmi *vc4_hdmi,
> - struct drm_modeset_acquire_ctx *ctx,
> - enum drm_connector_status status)
> -{
> - struct drm_connector *connector = &vc4_hdmi->connector;
> -
> - /*
> - * NOTE: This function should really be called with vc4_hdmi->mutex
> - * held, but doing so results in reentrancy issues since
> - * cec_s_phys_addr() might call .adap_enable, which leads to that
> - * funtion being called with our mutex held.
> - *
> - * A similar situation occurs with vc4_hdmi_reset_link() that
> - * will call into our KMS hooks if the scrambling was enabled.
> - *
> - * Concurrency isn't an issue at the moment since we don't share
> - * any state with any of the other frameworks so we can ignore
> - * the lock for now.
> - */
> -
> - drm_atomic_helper_connector_hdmi_hotplug(connector, ctx, status);
> -
> - if (status != connector_status_connected)
> - return 0;
> -
> - return vc4_hdmi_reset_link(connector, ctx);
> -}
> -
> static int vc4_hdmi_connector_detect_ctx(struct drm_connector *connector,
> struct drm_modeset_acquire_ctx *ctx,
> bool force)
> @@ -383,8 +257,8 @@ static int vc4_hdmi_connector_detect_ctx(struct
> drm_connector *connector,
> /*
> * NOTE: This function should really take vc4_hdmi->mutex, but
> * doing so results in reentrancy issues since
> - * vc4_hdmi_handle_hotplug() can call into other functions that
> - * would take the mutex while it's held here.
> + * drm_atomic_helper_connector_hdmi_hotplug() can call into other
> + * functions that would take the mutex while it's held here.
> *
> * Concurrency isn't an issue at the moment since we don't share
> * any state with any of the other frameworks so we can ignore
> @@ -407,7 +281,8 @@ static int vc4_hdmi_connector_detect_ctx(struct
> drm_connector *connector,
> status = connector_status_connected;
> }
>
> - ret = vc4_hdmi_handle_hotplug(vc4_hdmi, ctx, status);
> + ret = drm_atomic_helper_connector_hdmi_hotplug(connector, ctx, status);
> +
> pm_runtime_put(&vc4_hdmi->pdev->dev);
>
> return ret == -EDEADLK ? ret : status;
> @@ -534,6 +409,14 @@ static int vc4_hdmi_connector_init(struct drm_device
> *dev,
>
> drm_connector_helper_add(connector, &vc4_hdmi_connector_helper_funcs);
>
> + /*
> + * Since we don't know the state of the controller and its
> + * display (if any), let's assume it's always enabled.
> + * drm_connector_hdmi_disable_scrambling() will thus run at boot,
> + * make sure it's disabled, and avoid any inconsistency.
> + */
> + connector->hdmi.scrambler_enabled =
> drm_connector_hdmi_scrambler_supported(connector);
> +
> /*
> * Some of the properties below require access to state, like bpc.
> * Allocate some default initial connector state with our reset helper.
> @@ -759,32 +642,15 @@ static int vc4_hdmi_write_spd_infoframe(struct
> drm_connector *connector,
> buffer, len);
> }
>
> -#define SCRAMBLING_POLLING_DELAY_MS 1000
> -
> -static void vc4_hdmi_enable_scrambling(struct drm_encoder *encoder)
> +static int vc4_hdmi_scrambler_enable(struct drm_connector *connector)
> {
> - struct vc4_hdmi *vc4_hdmi = encoder_to_vc4_hdmi(encoder);
> - struct drm_connector *connector = &vc4_hdmi->connector;
> + struct vc4_hdmi *vc4_hdmi = connector_to_vc4_hdmi(connector);
> struct drm_device *drm = connector->dev;
> - const struct drm_display_mode *mode = &vc4_hdmi->saved_adjusted_mode;
> unsigned long flags;
> int idx;
>
> - lockdep_assert_held(&vc4_hdmi->mutex);
> -
> - if (!vc4_hdmi_supports_scrambling(vc4_hdmi))
> - return;
> -
> - if (!drm_hdmi_mode_needs_scrambling(mode,
> - vc4_hdmi->output_bpc,
> - vc4_hdmi->output_format))
> - return;
> -
> if (!drm_dev_enter(drm, &idx))
> - return;
> -
> - drm_scdc_set_high_tmds_clock_ratio(connector, true);
> - drm_scdc_set_scrambling(connector, true);
> + return -ENODEV;
Not being able to acquire the device isn't an error, it's something we should
ignore.
>
> spin_lock_irqsave(&vc4_hdmi->hw_lock, flags);
> HDMI_WRITE(HDMI_SCRAMBLER_CTL, HDMI_READ(HDMI_SCRAMBLER_CTL) |
> @@ -793,59 +659,27 @@ static void vc4_hdmi_enable_scrambling(struct
> drm_encoder *encoder)
>
> drm_dev_exit(idx);
>
> - vc4_hdmi->scdc_enabled = true;
> -
> - queue_delayed_work(system_percpu_wq, &vc4_hdmi->scrambling_work,
> - msecs_to_jiffies(SCRAMBLING_POLLING_DELAY_MS));
> + return 0;
> }
>
> -static void vc4_hdmi_disable_scrambling(struct drm_encoder *encoder)
> +static int vc4_hdmi_scrambler_disable(struct drm_connector *connector)
> {
> - struct vc4_hdmi *vc4_hdmi = encoder_to_vc4_hdmi(encoder);
> - struct drm_connector *connector = &vc4_hdmi->connector;
> + struct vc4_hdmi *vc4_hdmi = connector_to_vc4_hdmi(connector);
> struct drm_device *drm = connector->dev;
> unsigned long flags;
> int idx;
>
> - lockdep_assert_held(&vc4_hdmi->mutex);
> -
> - if (!vc4_hdmi->scdc_enabled)
> - return;
> -
> - vc4_hdmi->scdc_enabled = false;
> -
> - if (delayed_work_pending(&vc4_hdmi->scrambling_work))
> - cancel_delayed_work_sync(&vc4_hdmi->scrambling_work);
> -
> if (!drm_dev_enter(drm, &idx))
> - return;
> + return -ENODEV;
Ditto
Maxime
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