From c463b4ad6b2ac5a40c959e6c636eafc7edb1a63b Mon Sep 17 00:00:00 2001
From: Gerd Hoffmann <kraxel@redhat.com>
Date: Wed, 6 Sep 2017 11:31:51 +0200
Subject: qxl: fix primary surface handling
Patch-mainline: No, testing
References: bsc#1057241,bsc#1057123

The atomic conversion of the qxl driver didn't got the primary surface
handling completely right.  It works in the common simple cases, but
fails for example when changing the display resolution using xrandr or
in multihead setups.

The rules are simple:  There is one primary surface.  Before defining a
new one you have to destroy the old one.

This patch makes qxl_primary_atomic_update() destroy the primary surface
before defining a new one.  It fixes is_primary flag updates.  It adds
is_primary checks so we don't try to update the primary surface in case
it already has the state we want it being in.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/gpu/drm/qxl/qxl_display.c |   34 +++++++++++++++++++---------------
 1 file changed, 19 insertions(+), 15 deletions(-)

--- a/drivers/gpu/drm/qxl/qxl_display.c
+++ b/drivers/gpu/drm/qxl/qxl_display.c
@@ -513,23 +513,25 @@ static void qxl_primary_atomic_update(st
 	    .y2 = qfb->base.height
 	};
 
-	if (!old_state->fb) {
-		qxl_io_log(qdev,
-			   "create primary fb: %dx%d,%d,%d\n",
-			   bo->surf.width, bo->surf.height,
-			   bo->surf.stride, bo->surf.format);
+	if (old_state->fb) {
+		qfb_old = to_qxl_framebuffer(old_state->fb);
+		bo_old = gem_to_qxl_bo(qfb_old->obj);
+	} else {
+		bo_old = NULL;
+	}
 
-		qxl_io_create_primary(qdev, 0, bo);
-		bo->is_primary = true;
+	if (bo == bo_old)
 		return;
 
-	} else {
-		qfb_old = to_qxl_framebuffer(old_state->fb);
-		bo_old = gem_to_qxl_bo(qfb_old->obj);
+	if (bo_old && bo_old->is_primary) {
+		qxl_io_destroy_primary(qdev);
 		bo_old->is_primary = false;
 	}
 
-	bo->is_primary = true;
+	if (!bo->is_primary) {
+		qxl_io_create_primary(qdev, 0, bo);
+		bo->is_primary = true;
+	}
 	qxl_draw_dirty_fb(qdev, qfb, bo, 0, 0, &norect, 1, 1);
 }
 
@@ -538,13 +540,15 @@ static void qxl_primary_atomic_disable(s
 {
 	struct qxl_device *qdev = plane->dev->dev_private;
 
-	if (old_state->fb)
-	{	struct qxl_framebuffer *qfb =
+	if (old_state->fb) {
+		struct qxl_framebuffer *qfb =
 			to_qxl_framebuffer(old_state->fb);
 		struct qxl_bo *bo = gem_to_qxl_bo(qfb->obj);
 
-		qxl_io_destroy_primary(qdev);
-		bo->is_primary = false;
+		if (bo->is_primary) {
+			qxl_io_destroy_primary(qdev);
+			bo->is_primary = false;
+		}
 	}
 }