From d6c02ffd9c910637f6b3b7249507998e9e45f93c Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=C5=81ukasz=20Spintzyk?= <lukasz.spintzyk@synaptics.com>
Date: Mon, 19 Jul 2021 14:25:28 +0200
Subject: [PATCH] present: fallback get_crtc to return crtc belonging to screen
 with present extension

Since crtc can belong to secondary output that may not have present
extension enabled we should fallback to first enabled crtc or fake crtc.

Fix for issue xorg/xserver#1195
---
 present/present.c | 10 +++++++++-
 randr/randr.c     | 27 +++++++++++++++++++++++++++
 randr/randrstr.h  |  2 ++
 3 files changed, 38 insertions(+), 1 deletion(-)

diff --git a/present/present.c b/present/present.c
index 217fe1d7a..271fe32bc 100644
--- a/present/present.c
+++ b/present/present.c
@@ -44,11 +44,19 @@ present_get_crtc(WindowPtr window)
 {
     ScreenPtr                   screen = window->drawable.pScreen;
     present_screen_priv_ptr     screen_priv = present_screen_priv(screen);
+    RRCrtcPtr                   crtc = NULL;
 
     if (!screen_priv)
         return NULL;
 
-    return screen_priv->get_crtc(screen_priv, window);
+    crtc = screen_priv->get_crtc(screen_priv, window);
+    if (crtc && !present_screen_priv(crtc->pScreen)) {
+        crtc = RRFirstEnabledCrtc(screen);
+    }
+    if (crtc && !present_screen_priv(crtc->pScreen)) {
+        crtc = NULL;
+    }
+    return crtc;
 }
 
 /*
diff --git a/randr/randr.c b/randr/randr.c
index 3f94c2f6c..6d02c2577 100644
--- a/randr/randr.c
+++ b/randr/randr.c
@@ -697,6 +697,33 @@ RRFirstOutput(ScreenPtr pScreen)
     return NULL;
 }
 
+RRCrtcPtr
+RRFirstEnabledCrtc(ScreenPtr pScreen)
+{
+    rrScrPriv(pScreen);
+    RROutputPtr output;
+    int i, j;
+
+    if (!pScrPriv)
+        return NULL;
+
+    if (pScrPriv->primaryOutput && pScrPriv->primaryOutput->crtc &&
+        pScrPriv->primaryOutput->pScreen == pScreen)
+        return pScrPriv->primaryOutput->crtc;
+
+    for (i = 0; i < pScrPriv->numCrtcs; i++) {
+        RRCrtcPtr crtc = pScrPriv->crtcs[i];
+
+        for (j = 0; j < pScrPriv->numOutputs; j++) {
+            output = pScrPriv->outputs[j];
+            if (output->crtc == crtc && crtc->mode)
+                return crtc;
+        }
+    }
+    return NULL;
+}
+
+
 CARD16
 RRVerticalRefresh(xRRModeInfo * mode)
 {
diff --git a/randr/randrstr.h b/randr/randrstr.h
index 8f427a48e..b23390575 100644
--- a/randr/randrstr.h
+++ b/randr/randrstr.h
@@ -593,6 +593,8 @@ extern _X_EXPORT Bool RRScreenInit(ScreenPtr pScreen);
 
 extern _X_EXPORT RROutputPtr RRFirstOutput(ScreenPtr pScreen);
 
+extern _X_EXPORT RRCrtcPtr RRFirstEnabledCrtc(ScreenPtr pScreen);
+
 extern _X_EXPORT Bool RROutputSetNonDesktop(RROutputPtr output, Bool non_desktop);
 
 extern _X_EXPORT CARD16