[PATCH] xfree86: Strip dangling pointers from desiredMode

[Maarten Lankhorst]

Based on the original patch by Chris Wilson, which was a better fix than mine.

Signed-off-by: Maarten Lankhorst <maarten.lankhorst at canonical.com>

---
X-Bikeshed-Color: http://darkkhaki.bikeshed.com/

diff --git a/hw/xfree86/common/xf86.h b/hw/xfree86/common/xf86.h
index 129660d..0a90060 100644
--- a/hw/xfree86/common/xf86.h
+++ b/hw/xfree86/common/xf86.h
@@ -417,6 +417,8 @@ extern _X_EXPORT void
 xf86SetModeCrtc(DisplayModePtr p, int adjustFlags);
 extern _X_EXPORT DisplayModePtr
 xf86DuplicateMode(const DisplayModeRec * pMode);
+extern _X_EXPORT void
+xf86SaveModeContents(DisplayModePtr intern, const DisplayModeRec * pMode);
 extern _X_EXPORT DisplayModePtr
 xf86DuplicateModes(ScrnInfoPtr pScrn, DisplayModePtr modeList);
 extern _X_EXPORT Bool
diff --git a/hw/xfree86/modes/xf86Crtc.c b/hw/xfree86/modes/xf86Crtc.c
index 2c8878f..fb3eda5 100644
--- a/hw/xfree86/modes/xf86Crtc.c
+++ b/hw/xfree86/modes/xf86Crtc.c
@@ -2436,7 +2436,7 @@ xf86InitialConfiguration(ScrnInfoPtr scrn, Bool canGrow)
         xf86CrtcPtr crtc = crtcs[o];
 
         if (mode && crtc) {
-            crtc->desiredMode = *mode;
+            xf86SaveModeContents(&crtc->desiredMode, mode);
             crtc->desiredRotation = output->initial_rotation;
             crtc->desiredX = output->initial_x;
             crtc->desiredY = output->initial_y;
@@ -2620,7 +2620,7 @@ xf86SetDesiredModes(ScrnInfoPtr scrn)
 
             if (!mode)
                 return FALSE;
-            crtc->desiredMode = *mode;
+            xf86SaveModeContents(&crtc->desiredMode, mode);
             crtc->desiredRotation = RR_Rotate_0;
             crtc->desiredTransformPresent = FALSE;
             crtc->desiredX = 0;
@@ -2759,7 +2759,7 @@ xf86SetSingleMode(ScrnInfoPtr pScrn, DisplayModePtr desired, Rotation rotation)
         if (!xf86CrtcSetModeTransform(crtc, crtc_mode, rotation, NULL, 0, 0))
             ok = FALSE;
         else {
-            crtc->desiredMode = *crtc_mode;
+            xf86SaveModeContents(&crtc->desiredMode, crtc_mode);
             crtc->desiredRotation = rotation;
             crtc->desiredTransformPresent = FALSE;
             crtc->desiredX = 0;
diff --git a/hw/xfree86/modes/xf86Modes.c b/hw/xfree86/modes/xf86Modes.c
index 2a6d267..c4a3eb0 100644
--- a/hw/xfree86/modes/xf86Modes.c
+++ b/hw/xfree86/modes/xf86Modes.c
@@ -191,6 +191,21 @@ xf86SetModeCrtc(DisplayModePtr p, int adjustFlags)
 }
 
 /**
+ * Fills in a copy of mode, removing all stale pointer references.
+ * xf86ModesEqual will return true when comparing with original mode.
+ */
+void
+xf86SaveModeContents(DisplayModePtr intern, const DisplayModeRec *mode)
+{
+    *intern = *mode;
+    intern->prev = intern->next = NULL;
+    intern->name = NULL;
+    intern->PrivSize = 0;
+    intern->PrivFlags = 0;
+    intern->Private = NULL;
+}
+
+/**
  * Allocates and returns a copy of pMode, including pointers within pMode.
  */
 DisplayModePtr
diff --git a/hw/xfree86/modes/xf86RandR12.c b/hw/xfree86/modes/xf86RandR12.c
index 59b6f82..8bce801 100644
--- a/hw/xfree86/modes/xf86RandR12.c
+++ b/hw/xfree86/modes/xf86RandR12.c
@@ -1216,7 +1216,7 @@ xf86RandR12CrtcSet(ScreenPtr pScreen,
             /*
              * Save the last successful setting for EnterVT
              */
-            crtc->desiredMode = mode;
+            xf86SaveModeContents(&crtc->desiredMode, &mode);
             crtc->desiredRotation = rotation;
             if (transform) {
                 crtc->desiredTransform = *transform;