From 5489029ff6508b37d71d47d905d744c436a49563 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Michel=20D=C3=A4nzer?= <mdaenzer@redhat.com>
Date: Tue, 26 Nov 2019 17:17:12 +0100
Subject: [PATCH xserver 3/3] modesetting: Clear new screen pixmap storage on
 RandR resize
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Fixes random garbage being visible intermittently.

Reviewed-by: Adam Jackson <ajax@redhat.com>
(Cherry picked from commit 9ba13bac9dd076f166ff0d063fc144b904a40d12)

Signed-off-by: Michel Dänzer <mdaenzer@redhat.com>
---
 hw/xfree86/drivers/modesetting/drmmode_display.c | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/hw/xfree86/drivers/modesetting/drmmode_display.c b/hw/xfree86/drivers/modesetting/drmmode_display.c
index 8786d13a3..eca058258 100644
--- a/hw/xfree86/drivers/modesetting/drmmode_display.c
+++ b/hw/xfree86/drivers/modesetting/drmmode_display.c
@@ -1795,6 +1795,19 @@ drmmode_set_scanout_pixmap(xf86CrtcPtr crtc, PixmapPtr ppix)
                                              &drmmode_crtc->prime_pixmap);
 }
 
+static void
+drmmode_clear_pixmap(PixmapPtr pixmap)
+{
+    ScreenPtr screen = pixmap->drawable.pScreen;
+    GCPtr gc;
+
+    gc = GetScratchGC(pixmap->drawable.depth, screen);
+    if (gc) {
+        miClearDrawable(&pixmap->drawable, gc);
+        FreeScratchGC(gc);
+    }
+}
+
 static void *
 drmmode_shadow_allocate(xf86CrtcPtr crtc, int width, int height)
 {
@@ -3179,6 +3192,8 @@ drmmode_xf86crtc_resize(ScrnInfoPtr scrn, int width, int height)
     if (!drmmode_glamor_handle_new_screen_pixmap(drmmode))
         goto fail;
 
+    drmmode_clear_pixmap(ppix);
+
     for (i = 0; i < xf86_config->num_crtc; i++) {
         xf86CrtcPtr crtc = xf86_config->crtc[i];
 
-- 
2.24.0