From ae85d3f7475ab61c70c39481ede4e3720c612ffa Mon Sep 17 00:00:00 2001
From: Brian Norris <briannorris@chromium.org>
Date: Mon, 28 Feb 2022 12:25:31 -0800
Subject: drm/bridge: analogix_dp: Support PSR-exit to disable transition
Git-commit: ca871659ec1606d33b1e76de8d4cf924cf627e34
Patch-mainline: v5.19-rc2
References: jsc#PED-1166 jsc#PED-1168 jsc#PED-1170 jsc#PED-1218 jsc#PED-1220 jsc#PED-1222 jsc#PED-1223 jsc#PED-1225

Most eDP panel functions only work correctly when the panel is not in
self-refresh. In particular, analogix_dp_bridge_disable() tends to hit
AUX channel errors if the panel is in self-refresh.

Given the above, it appears that so far, this driver assumes that we are
never in self-refresh when it comes time to fully disable the bridge.
Prior to commit 846c7dfc1193 ("drm/atomic: Try to preserve the crtc
enabled state in drm_atomic_remove_fb, v2."), this tended to be true,
because we would automatically disable the pipe when framebuffers were
removed, and so we'd typically disable the bridge shortly after the last
display activity.

However, that is not guaranteed: an idle (self-refresh) display pipe may
be disabled, e.g., when switching CRTCs. We need to exit PSR first.

Stable notes: this is definitely a bugfix, and the bug has likely
existed in some form for quite a while. It may predate the "PSR helpers"
refactor, but the code looked very different before that, and it's
probably not worth rewriting the fix.

Cc: <stable@vger.kernel.org>
Fixes: 6c836d965bad ("drm/rockchip: Use the helpers for PSR")
Signed-off-by: Brian Norris <briannorris@chromium.org>
Reviewed-by: Sean Paul <seanpaul@chromium.org>
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20220228122522.v2.1.I161904be17ba14526f78536ccd78b85818449b51@changeid
Acked-by: Patrik Jakobsson <pjakobsson@suse.de>
---
 .../drm/bridge/analogix/analogix_dp_core.c    | 42 +++++++++++++++++--
 1 file changed, 38 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
index b97f6e8f0f6b..01c8b80e34ec 100644
--- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
+++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
@@ -1266,6 +1266,25 @@ static int analogix_dp_bridge_attach(struct drm_bridge *bridge,
 	return 0;
 }
 
+static
+struct drm_crtc *analogix_dp_get_old_crtc(struct analogix_dp_device *dp,
+					  struct drm_atomic_state *state)
+{
+	struct drm_encoder *encoder = dp->encoder;
+	struct drm_connector *connector;
+	struct drm_connector_state *conn_state;
+
+	connector = drm_atomic_get_old_connector_for_encoder(state, encoder);
+	if (!connector)
+		return NULL;
+
+	conn_state = drm_atomic_get_old_connector_state(state, connector);
+	if (!conn_state)
+		return NULL;
+
+	return conn_state->crtc;
+}
+
 static
 struct drm_crtc *analogix_dp_get_new_crtc(struct analogix_dp_device *dp,
 					  struct drm_atomic_state *state)
@@ -1446,14 +1465,16 @@ analogix_dp_bridge_atomic_disable(struct drm_bridge *bridge,
 {
 	struct drm_atomic_state *old_state = old_bridge_state->base.state;
 	struct analogix_dp_device *dp = bridge->driver_private;
-	struct drm_crtc *crtc;
+	struct drm_crtc *old_crtc, *new_crtc;
+	struct drm_crtc_state *old_crtc_state = NULL;
 	struct drm_crtc_state *new_crtc_state = NULL;
+	int ret;
 
-	crtc = analogix_dp_get_new_crtc(dp, old_state);
-	if (!crtc)
+	new_crtc = analogix_dp_get_new_crtc(dp, old_state);
+	if (!new_crtc)
 		goto out;
 
-	new_crtc_state = drm_atomic_get_new_crtc_state(old_state, crtc);
+	new_crtc_state = drm_atomic_get_new_crtc_state(old_state, new_crtc);
 	if (!new_crtc_state)
 		goto out;
 
@@ -1462,6 +1483,19 @@ analogix_dp_bridge_atomic_disable(struct drm_bridge *bridge,
 		return;
 
 out:
+	old_crtc = analogix_dp_get_old_crtc(dp, old_state);
+	if (old_crtc) {
+		old_crtc_state = drm_atomic_get_old_crtc_state(old_state,
+							       old_crtc);
+
+		/* When moving from PSR to fully disabled, exit PSR first. */
+		if (old_crtc_state && old_crtc_state->self_refresh_active) {
+			ret = analogix_dp_disable_psr(dp);
+			if (ret)
+				DRM_ERROR("Failed to disable psr (%d)\n", ret);
+		}
+	}
+
 	analogix_dp_bridge_disable(bridge);
 }
 
-- 
2.38.1