[PATCH 3/4] drm/i915/panel: register drm_panel and call prepare/unprepare for ICL+ DSI
Lee, Shawn C
shawn.c.lee at intel.com
Fri Jun 6 15:50:48 UTC 2025
On June 6, 2025, 9:05, Jani Nikula <jani.nikula at intel.com> wrote:
>Allocate and register a drm_panel so that drm_panel_followers can find the panel. Pass the drm_connector::kdev device to drm_panel allocation for matching. That's only available after drm_sysfs_connector_add(), so we need to postpone the drm_panel allocation until .late_register() hook.
>
>The drm_panel framework is moving towards devm_drm_panel_alloc(). It requires a wrapper struct, and struct intel_panel would be the natural candidate. However, we can't postpone its allocation until .late_register(), so we have to use __devm_drm_panel_alloc() directly for now.
>
>Call the drm_panel_prepare() and drm_panel_unprepare() functions for
>ICL+ DSI, so that followers get notified of the panel power state
>changes. This can later be expanded to VLV+ DSI and eDP.
>
>Cc: Maxime Ripard <mripard at kernel.org>
>Cc: Heikki Krogerus <heikki.krogerus at linux.intel.com>
>Cc: Lee Shawn C <shawn.c.lee at intel.com>
>Signed-off-by: Jani Nikula <jani.nikula at intel.com>
This patch series was tested on my local device. And panel follower works well on it.
Tested-by: Lee Shawn C <shawn.c.lee at intel.com>
>---
> drivers/gpu/drm/i915/display/icl_dsi.c | 4 +
> .../drm/i915/display/intel_display_types.h | 4 +
> drivers/gpu/drm/i915/display/intel_panel.c | 82 ++++++++++++++++++-
> drivers/gpu/drm/i915/display/intel_panel.h | 4 +
> 4 files changed, 93 insertions(+), 1 deletion(-)
>
>diff --git a/drivers/gpu/drm/i915/display/icl_dsi.c b/drivers/gpu/drm/i915/display/icl_dsi.c
>index 026361354e6f..81410b3aed51 100644
>--- a/drivers/gpu/drm/i915/display/icl_dsi.c
>+++ b/drivers/gpu/drm/i915/display/icl_dsi.c
>@@ -1276,6 +1276,8 @@ static void gen11_dsi_enable(struct intel_atomic_state *state,
> intel_backlight_enable(crtc_state, conn_state);
> intel_dsi_vbt_exec_sequence(intel_dsi, MIPI_SEQ_BACKLIGHT_ON);
>
>+ intel_panel_prepare(crtc_state, conn_state);
>+
> intel_crtc_vblank_on(crtc_state);
> }
>
>@@ -1409,6 +1411,8 @@ static void gen11_dsi_disable(struct intel_atomic_state *state, {
> struct intel_dsi *intel_dsi = enc_to_intel_dsi(encoder);
>
>+ intel_panel_unprepare(old_conn_state);
>+
> /* step1: turn off backlight */
> intel_dsi_vbt_exec_sequence(intel_dsi, MIPI_SEQ_BACKLIGHT_OFF);
> intel_backlight_disable(old_conn_state);
>diff --git a/drivers/gpu/drm/i915/display/intel_display_types.h b/drivers/gpu/drm/i915/display/intel_display_types.h
>index ed4d743fc7c5..30c7315fc25e 100644
>--- a/drivers/gpu/drm/i915/display/intel_display_types.h
>+++ b/drivers/gpu/drm/i915/display/intel_display_types.h
>@@ -37,6 +37,7 @@
> #include <drm/drm_crtc.h>
> #include <drm/drm_encoder.h>
> #include <drm/drm_framebuffer.h>
>+#include <drm/drm_panel.h>
> #include <drm/drm_rect.h>
> #include <drm/drm_vblank_work.h>
> #include <drm/intel/i915_hdcp_interface.h> @@ -384,6 +385,9 @@ struct intel_vbt_panel_data { };
>
> struct intel_panel {
>+ /* Simple drm_panel */
>+ struct drm_panel *base;
>+
> /* Fixed EDID for eDP and LVDS. May hold ERR_PTR for invalid EDID. */
> const struct drm_edid *fixed_edid;
>
>diff --git a/drivers/gpu/drm/i915/display/intel_panel.c b/drivers/gpu/drm/i915/display/intel_panel.c
>index 5ae302bee191..b1d549e6cf53 100644
>--- a/drivers/gpu/drm/i915/display/intel_panel.c
>+++ b/drivers/gpu/drm/i915/display/intel_panel.c
>@@ -463,12 +463,92 @@ void intel_panel_fini(struct intel_connector *connector)
> }
> }
>
>+const struct drm_panel_funcs dummy_panel_funcs = { };
>+
> int intel_panel_register(struct intel_connector *connector) {
>- return intel_backlight_device_register(connector);
>+ struct intel_display *display = to_intel_display(connector);
>+ struct intel_panel *panel = &connector->panel;
>+ int ret;
>+
>+ ret = intel_backlight_device_register(connector);
>+ if (ret)
>+ return ret;
>+
>+ if (connector->base.connector_type == DRM_MODE_CONNECTOR_DSI) {
>+ struct device *dev = connector->base.kdev;
>+ struct drm_panel *base;
>+
>+ /* Sanity check. */
>+ if (drm_WARN_ON(display->drm, !dev))
>+ goto out;
>+
>+ /*
>+ * We need drm_connector::kdev for allocating the panel, to make
>+ * drm_panel_add_follower() lookups work. The kdev is
>+ * initialized in drm_sysfs_connector_add(), just before the
>+ * connector .late_register() hooks. So we can't allocate the
>+ * panel at connector init time, and can't allocate struct
>+ * intel_panel with a drm_panel sub-struct. For now, use
>+ * __devm_drm_panel_alloc() directly.
>+ *
>+ * The lookups also depend on drm_connector::fwnode being set in
>+ * intel_acpi_assign_connector_fwnodes(). However, if that's
>+ * missing, it will gracefully lead to -EPROBE_DEFER in
>+ * drm_panel_add_follower().
>+ */
>+ base = __devm_drm_panel_alloc(dev, sizeof(*base), 0,
>+ &dummy_panel_funcs,
>+ connector->base.connector_type);
>+ if (IS_ERR(base)) {
>+ ret = PTR_ERR(base);
>+ goto err;
>+ }
>+
>+ panel->base = base;
>+
>+ drm_panel_add(panel->base);
>+
>+ drm_dbg_kms(display->drm, "[CONNECTOR:%d:%s] Registered panel device '%s', has fwnode: %s\n",
>+ connector->base.base.id, connector->base.name,
>+ dev_name(dev), str_yes_no(dev_fwnode(dev)));
>+ }
>+
>+out:
>+ return 0;
>+
>+err:
>+ intel_backlight_device_unregister(connector);
>+
>+ return ret;
> }
>
> void intel_panel_unregister(struct intel_connector *connector) {
>+ struct intel_panel *panel = &connector->panel;
>+
>+ if (panel->base)
>+ drm_panel_remove(panel->base);
>+
> intel_backlight_device_unregister(connector);
> }
>+
>+/* Notify followers, if any, about power being up. */ void
>+intel_panel_prepare(const struct intel_crtc_state *crtc_state,
>+ const struct drm_connector_state *conn_state) {
>+ struct intel_connector *connector = to_intel_connector(conn_state->connector);
>+ struct intel_panel *panel = &connector->panel;
>+
>+ drm_panel_prepare(panel->base);
>+}
>+
>+/* Notify followers, if any, about power going down. */ void
>+intel_panel_unprepare(const struct drm_connector_state *old_conn_state)
>+{
>+ struct intel_connector *connector = to_intel_connector(old_conn_state->connector);
>+ struct intel_panel *panel = &connector->panel;
>+
>+ drm_panel_unprepare(panel->base);
>+}
>diff --git a/drivers/gpu/drm/i915/display/intel_panel.h b/drivers/gpu/drm/i915/display/intel_panel.h
>index 3d592a4404f3..56a6412cf0fb 100644
>--- a/drivers/gpu/drm/i915/display/intel_panel.h
>+++ b/drivers/gpu/drm/i915/display/intel_panel.h
>@@ -53,4 +53,8 @@ void intel_panel_add_vbt_sdvo_fixed_mode(struct intel_connector *connector); void intel_panel_add_encoder_fixed_mode(struct intel_connector *connector,
> struct intel_encoder *encoder);
>
>+void intel_panel_prepare(const struct intel_crtc_state *crtc_state,
>+ const struct drm_connector_state *conn_state); void
>+intel_panel_unprepare(const struct drm_connector_state
>+*old_conn_state);
>+
> #endif /* __INTEL_PANEL_H__ */
>--
>2.39.5
>
>
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