--- /dev/null
+From 7cd70656d1285b79c001f041a017fcfee4292ff9 Mon Sep 17 00:00:00 2001
+From: Neil Armstrong <narmstrong@baylibre.com>
+Date: Wed, 20 Oct 2021 14:39:42 +0200
+Subject: drm/bridge: display-connector: implement bus fmts callbacks
+
+From: Neil Armstrong <narmstrong@baylibre.com>
+
+commit 7cd70656d1285b79c001f041a017fcfee4292ff9 upstream.
+
+Since this bridge is tied to the connector, it acts like a passthrough,
+so concerning the output & input bus formats, either pass the bus formats from the
+previous bridge or return fallback data like done in the bridge function:
+drm_atomic_bridge_chain_select_bus_fmts() & select_bus_fmt_recursive.
+
+This permits avoiding skipping the negociation if the remaining bridge chain has
+all the bits in place.
+
+Without this bus fmt negociation breaks on drm/meson HDMI pipeline when attaching
+dw-hdmi with DRM_BRIDGE_ATTACH_NO_CONNECTOR, because the last bridge of the
+display-connector doesn't implement buf fmt callbacks and MEDIA_BUS_FMT_FIXED
+is used leading to select an unsupported default bus format from dw-hdmi.
+
+Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
+Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
+Link: https://patchwork.freedesktop.org/patch/msgid/20211020123947.2585572-2-narmstrong@baylibre.com
+Cc: Stefan Agner <stefan@agner.ch>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ drivers/gpu/drm/bridge/display-connector.c | 86 +++++++++++++++++++++++++++++
+ 1 file changed, 86 insertions(+)
+
+--- a/drivers/gpu/drm/bridge/display-connector.c
++++ b/drivers/gpu/drm/bridge/display-connector.c
+@@ -13,6 +13,7 @@
+ #include <linux/platform_device.h>
+ #include <linux/regulator/consumer.h>
+
++#include <drm/drm_atomic_helper.h>
+ #include <drm/drm_bridge.h>
+ #include <drm/drm_edid.h>
+
+@@ -87,10 +88,95 @@ static struct edid *display_connector_ge
+ return drm_get_edid(connector, conn->bridge.ddc);
+ }
+
++/*
++ * Since this bridge is tied to the connector, it acts like a passthrough,
++ * so concerning the output bus formats, either pass the bus formats from the
++ * previous bridge or return fallback data like done in the bridge function:
++ * drm_atomic_bridge_chain_select_bus_fmts().
++ * This supports negotiation if the bridge chain has all bits in place.
++ */
++static u32 *display_connector_get_output_bus_fmts(struct drm_bridge *bridge,
++ struct drm_bridge_state *bridge_state,
++ struct drm_crtc_state *crtc_state,
++ struct drm_connector_state *conn_state,
++ unsigned int *num_output_fmts)
++{
++ struct drm_bridge *prev_bridge = drm_bridge_get_prev_bridge(bridge);
++ struct drm_bridge_state *prev_bridge_state;
++
++ if (!prev_bridge || !prev_bridge->funcs->atomic_get_output_bus_fmts) {
++ struct drm_connector *conn = conn_state->connector;
++ u32 *out_bus_fmts;
++
++ *num_output_fmts = 1;
++ out_bus_fmts = kmalloc(sizeof(*out_bus_fmts), GFP_KERNEL);
++ if (!out_bus_fmts)
++ return NULL;
++
++ if (conn->display_info.num_bus_formats &&
++ conn->display_info.bus_formats)
++ out_bus_fmts[0] = conn->display_info.bus_formats[0];
++ else
++ out_bus_fmts[0] = MEDIA_BUS_FMT_FIXED;
++
++ return out_bus_fmts;
++ }
++
++ prev_bridge_state = drm_atomic_get_new_bridge_state(crtc_state->state,
++ prev_bridge);
++
++ return prev_bridge->funcs->atomic_get_output_bus_fmts(prev_bridge, prev_bridge_state,
++ crtc_state, conn_state,
++ num_output_fmts);
++}
++
++/*
++ * Since this bridge is tied to the connector, it acts like a passthrough,
++ * so concerning the input bus formats, either pass the bus formats from the
++ * previous bridge or MEDIA_BUS_FMT_FIXED (like select_bus_fmt_recursive())
++ * when atomic_get_input_bus_fmts is not supported.
++ * This supports negotiation if the bridge chain has all bits in place.
++ */
++static u32 *display_connector_get_input_bus_fmts(struct drm_bridge *bridge,
++ struct drm_bridge_state *bridge_state,
++ struct drm_crtc_state *crtc_state,
++ struct drm_connector_state *conn_state,
++ u32 output_fmt,
++ unsigned int *num_input_fmts)
++{
++ struct drm_bridge *prev_bridge = drm_bridge_get_prev_bridge(bridge);
++ struct drm_bridge_state *prev_bridge_state;
++
++ if (!prev_bridge || !prev_bridge->funcs->atomic_get_input_bus_fmts) {
++ u32 *in_bus_fmts;
++
++ *num_input_fmts = 1;
++ in_bus_fmts = kmalloc(sizeof(*in_bus_fmts), GFP_KERNEL);
++ if (!in_bus_fmts)
++ return NULL;
++
++ in_bus_fmts[0] = MEDIA_BUS_FMT_FIXED;
++
++ return in_bus_fmts;
++ }
++
++ prev_bridge_state = drm_atomic_get_new_bridge_state(crtc_state->state,
++ prev_bridge);
++
++ return prev_bridge->funcs->atomic_get_input_bus_fmts(prev_bridge, prev_bridge_state,
++ crtc_state, conn_state, output_fmt,
++ num_input_fmts);
++}
++
+ static const struct drm_bridge_funcs display_connector_bridge_funcs = {
+ .attach = display_connector_attach,
+ .detect = display_connector_detect,
+ .get_edid = display_connector_get_edid,
++ .atomic_get_output_bus_fmts = display_connector_get_output_bus_fmts,
++ .atomic_get_input_bus_fmts = display_connector_get_input_bus_fmts,
++ .atomic_duplicate_state = drm_atomic_helper_bridge_duplicate_state,
++ .atomic_destroy_state = drm_atomic_helper_bridge_destroy_state,
++ .atomic_reset = drm_atomic_helper_bridge_reset,
+ };
+
+ static irqreturn_t display_connector_hpd_irq(int irq, void *arg)
projects / thirdparty / kernel / stable-queue.git / commitdiff
