[PATCH] Add check for link from output to crtc before optimizing out a CrtcSet call

[David Sodman]

The function RRCrtcSet call checks to see if the config being set is
already configured, but, doesn't check that the selected outputs are
connected to the crtc before skipping.  This means that the following
sequence will omit the final CrtcSet call to the driver:

    CRTC c1 connect to output o
    CRTC c2 connect to output o
    CRTC c1 connect to output o

This change adds the check to ensure that each of the calls are made to
the driver.

Signed-off-by: David Sodman <dsodman at chromium.org>
Reviewed-by: Stephane Marchesin <marcheu at chromium.org>
---
 randr/rrcrtc.c | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/randr/rrcrtc.c b/randr/rrcrtc.c
index 6e181ba..2ecb43c 100644
--- a/randr/rrcrtc.c
+++ b/randr/rrcrtc.c
@@ -522,9 +522,19 @@ RRCrtcSet(RRCrtcPtr crtc,
     ScreenPtr pScreen = crtc->pScreen;
     Bool ret = FALSE;
     Bool recompute = TRUE;
+    Bool crtcChanged;
+    int  o;
 
     rrScrPriv(pScreen);
 
+    crtcChanged = FALSE;
+    for (o = 0; o < numOutputs; o++) {
+        if (outputs[o] && outputs[o]->crtc != crtc) {
+            crtcChanged = TRUE;
+            break;
+        }
+    }
+
     /* See if nothing changed */
     if (crtc->mode == mode &&
         crtc->x == x &&
@@ -532,7 +542,8 @@ RRCrtcSet(RRCrtcPtr crtc,
         crtc->rotation == rotation &&
         crtc->numOutputs == numOutputs &&
         !memcmp(crtc->outputs, outputs, numOutputs * sizeof(RROutputPtr)) &&
-        !RRCrtcPendingProperties(crtc) && !RRCrtcPendingTransform(crtc)) {
+        !RRCrtcPendingProperties(crtc) && !RRCrtcPendingTransform(crtc) &&
+        !crtcChanged) {
         recompute = FALSE;
         ret = TRUE;
     }
-- 
1.9.0.rc1.175.g0b1dcb5