HDMI Specification Version 1.4b chapter 8.5 mentions: An HDMI Sink shall not assert high voltage level on its Hot Plug Detect pin when the E-EDID is not available for reading.
A Source may use a high voltage level Hot Plug Detect signal to initiate the reading of E-EDID data. An HDMI Sink shall indicate any change to the contents of the E-EDID by driving a low voltage level pulse on the Hot Plug Detect pin. This pulse shall be at least 100 msec. Use a delayed work to debounce reacting on HPD events to improve handling of a HPD low voltage level pulse when a sink changes the EDID. The delayed work is only enabled between enable_hpd()/hpd_enable() and disable_hpd()/hpd_disable() calls from core, i.e. enabled after attach/bind/resume and disabled before detach/unbind/suspend. The 1100 msec hotplug debounce timeout was arbitrarily picked to match other drivers using same const, and testing using a Raspberry Pi Monitor seem to use a 200-300 msec pulse when going from standby to power on state. Signed-off-by: Jonas Karlman <[email protected]> --- v7: Change to free irq before mute and clear using IH regs, also include clear of STAT0_RX_SENSE v6: Change back to disable_delayed_work_sync() in hpd disable ops, Ensure HPD interrupt is masked and IRQ handler is disabled early in dw_hdmi_remove() to prevent any irq re-arming of delayed work, Drop use of suspend helper v5: Change to none-sync disable_delayed_work() in hpd disable ops, Change to cancel_delayed_work_sync() in remove, Add cancel_delayed_work_sync() to new suspend helper v4: Disable/mask delayed_work until enable_hpd()/hpd_enable(), Read connector status directly from HW regs in hpd_work v3: New patch --- drivers/gpu/drm/bridge/synopsys/dw-hdmi.c | 80 +++++++++++++++++++++-- 1 file changed, 75 insertions(+), 5 deletions(-) diff --git a/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c b/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c index 8afc9d240121..270db58a0e7c 100644 --- a/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c +++ b/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c @@ -50,6 +50,8 @@ #define HDMI14_MAX_TMDSCLK 340000000 +#define HOTPLUG_DEBOUNCE_MS 1100 + static const u16 csc_coeff_default[3][4] = { { 0x2000, 0x0000, 0x0000, 0x0000 }, { 0x0000, 0x2000, 0x0000, 0x0000 }, @@ -185,6 +187,7 @@ struct dw_hdmi { hdmi_codec_plugged_cb plugged_cb; struct device *codec_dev; enum drm_connector_status last_connector_result; + struct delayed_work hpd_work; }; const struct dw_hdmi_plat_data *dw_hdmi_to_plat_data(struct dw_hdmi *hdmi) @@ -2517,6 +2520,20 @@ static void dw_hdmi_connector_force(struct drm_connector *connector) dw_hdmi_connector_status_update(hdmi, connector, connector->status); } +static void dw_hdmi_connector_enable_hpd(struct drm_connector *connector) +{ + struct dw_hdmi *hdmi = container_of(connector, struct dw_hdmi, connector); + + enable_delayed_work(&hdmi->hpd_work); +} + +static void dw_hdmi_connector_disable_hpd(struct drm_connector *connector) +{ + struct dw_hdmi *hdmi = container_of(connector, struct dw_hdmi, connector); + + disable_delayed_work_sync(&hdmi->hpd_work); +} + static void dw_hdmi_connector_destroy(struct drm_connector *connector) { struct dw_hdmi *hdmi = container_of(connector, struct dw_hdmi, connector); @@ -2538,6 +2555,8 @@ static const struct drm_connector_funcs dw_hdmi_connector_funcs = { static const struct drm_connector_helper_funcs dw_hdmi_connector_helper_funcs = { .get_modes = dw_hdmi_connector_get_modes, .atomic_check = dw_hdmi_connector_atomic_check, + .enable_hpd = dw_hdmi_connector_enable_hpd, + .disable_hpd = dw_hdmi_connector_disable_hpd, }; static int dw_hdmi_connector_create(struct dw_hdmi *hdmi) @@ -2968,6 +2987,20 @@ static const struct drm_edid *dw_hdmi_bridge_edid_read(struct drm_bridge *bridge return dw_hdmi_edid_read(hdmi, connector); } +static void dw_hdmi_bridge_hpd_enable(struct drm_bridge *bridge) +{ + struct dw_hdmi *hdmi = bridge->driver_private; + + enable_delayed_work(&hdmi->hpd_work); +} + +static void dw_hdmi_bridge_hpd_disable(struct drm_bridge *bridge) +{ + struct dw_hdmi *hdmi = bridge->driver_private; + + disable_delayed_work_sync(&hdmi->hpd_work); +} + static const struct drm_bridge_funcs dw_hdmi_bridge_funcs = { .atomic_duplicate_state = drm_atomic_helper_bridge_duplicate_state, .atomic_destroy_state = drm_atomic_helper_bridge_destroy_state, @@ -2981,6 +3014,8 @@ static const struct drm_bridge_funcs dw_hdmi_bridge_funcs = { .mode_valid = dw_hdmi_bridge_mode_valid, .detect = dw_hdmi_bridge_detect, .edid_read = dw_hdmi_bridge_edid_read, + .hpd_enable = dw_hdmi_bridge_hpd_enable, + .hpd_disable = dw_hdmi_bridge_hpd_disable, }; /* ----------------------------------------------------------------------------- @@ -3101,8 +3136,8 @@ static irqreturn_t dw_hdmi_irq(int irq, void *dev_id) status == connector_status_connected ? "plugin" : "plugout"); - if (hdmi->bridge.dev) - drm_helper_hpd_irq_event(hdmi->bridge.dev); + mod_delayed_work(system_percpu_wq, &hdmi->hpd_work, + msecs_to_jiffies(HOTPLUG_DEBOUNCE_MS)); } hdmi_writeb(hdmi, intr_stat, HDMI_IH_PHY_STAT0); @@ -3112,6 +3147,29 @@ static irqreturn_t dw_hdmi_irq(int irq, void *dev_id) return IRQ_HANDLED; } +static void dw_hdmi_hpd_work(struct work_struct *work) +{ + struct dw_hdmi *hdmi = container_of(work, struct dw_hdmi, hpd_work.work); + struct drm_device *dev = hdmi->bridge.dev; + + if (WARN_ON(!dev)) + return; + + /* + * Notify the DRM core of the HPD event using drm_helper_hpd_irq_event() + * instead of drm_bridge_hpd_notify(). This will cause the DRM function + * check_connector_changed() to be called, which in turn calls the + * connector detect()/force() funcs to detect any connection status or + * epoch changes. The bridge connector detect() func also ensures that + * any hpd_notify() funcs are called for all bridges in the chain. + * + * drm_bridge_hpd_notify() shares a mutex with drm_bridge_hpd_disable(), + * and can result in a deadlock due to the disable_delayed_work_sync() + * call to wait on work to complete in dw_hdmi_bridge_hpd_disable(). + */ + drm_helper_hpd_irq_event(dev); +} + static const struct dw_hdmi_phy_data dw_hdmi_phys[] = { { .type = DW_HDMI_PHY_DWC_HDMI_TX_PHY, @@ -3396,6 +3454,9 @@ struct dw_hdmi *dw_hdmi_probe(struct platform_device *pdev, goto err_res; } + INIT_DELAYED_WORK(&hdmi->hpd_work, dw_hdmi_hpd_work); + disable_delayed_work(&hdmi->hpd_work); + ret = devm_request_threaded_irq(dev, irq, dw_hdmi_hardirq, dw_hdmi_irq, IRQF_SHARED, dev_name(dev), hdmi); @@ -3532,6 +3593,18 @@ EXPORT_SYMBOL_GPL(dw_hdmi_probe); void dw_hdmi_remove(struct dw_hdmi *hdmi) { + struct platform_device *pdev = to_platform_device(hdmi->dev); + int irq = platform_get_irq(pdev, 0); + + /* Free, mute and clear phy interrupts */ + devm_free_irq(hdmi->dev, irq, hdmi); + hdmi_writeb(hdmi, ~0, HDMI_IH_MUTE_PHY_STAT0); + hdmi_writeb(hdmi, HDMI_IH_PHY_STAT0_HPD | HDMI_IH_PHY_STAT0_RX_SENSE, + HDMI_IH_PHY_STAT0); + + /* Cancel any pending hot plug work */ + cancel_delayed_work_sync(&hdmi->hpd_work); + drm_bridge_remove(&hdmi->bridge); if (hdmi->audio && !IS_ERR(hdmi->audio)) @@ -3539,9 +3612,6 @@ void dw_hdmi_remove(struct dw_hdmi *hdmi) if (!IS_ERR(hdmi->cec)) platform_device_unregister(hdmi->cec); - /* Disable all interrupts */ - hdmi_writeb(hdmi, ~0, HDMI_IH_MUTE_PHY_STAT0); - if (hdmi->i2c) i2c_del_adapter(&hdmi->i2c->adap); else -- 2.54.0
