FAILED: patch "[PATCH] drm/bridge: analogix_dp: Support PSR-exit to disable" failed to apply to 5.4-stable tree

[<gregkh@linuxfoundation.org>]

The patch below does not apply to the 5.4-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From ca871659ec1606d33b1e76de8d4cf924cf627e34 Mon Sep 17 00:00:00 2001
From: Brian Norris <briannorris@chromium.org>
Date: Mon, 28 Feb 2022 12:25:31 -0800
Subject: [PATCH] drm/bridge: analogix_dp: Support PSR-exit to disable
 transition

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

diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
index eb590fb8e8d0..0300f670a4fd 100644
--- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
+++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
@@ -1268,6 +1268,25 @@ 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)
@@ -1448,14 +1467,16 @@ 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;
 
@@ -1464,6 +1485,19 @@ 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);
 }