[PATCH xf86-video-amdgpu] Don't set modes before AMDGPUWindowExposures_oneshot is called

[Michel Dänzer]

From: Michel Dänzer <michel.daenzer at amd.com>

The root window contents may be undefined before that, so we don't to
show anything yet.

Fixes a crash on startup with rotation and virtual resolution set in
xorg.conf.

Bugzilla: https://bugs.freedesktop.org/100276
Signed-off-by: Michel Dänzer <michel.daenzer at amd.com>
---
 src/amdgpu_drv.h      | 5 +++++
 src/amdgpu_kms.c      | 6 +++---
 src/drmmode_display.c | 6 ++++++
 3 files changed, 14 insertions(+), 3 deletions(-)

diff --git a/src/amdgpu_drv.h b/src/amdgpu_drv.h
index 532d99daa..e5c44dc36 100644
--- a/src/amdgpu_drv.h
+++ b/src/amdgpu_drv.h
@@ -315,6 +315,11 @@ Bool amdgpu_dri3_screen_init(ScreenPtr screen);
 
 /* amdgpu_kms.c */
 Bool amdgpu_scanout_do_update(xf86CrtcPtr xf86_crtc, int scanout_id);
+void AMDGPUWindowExposures_oneshot(WindowPtr pWin, RegionPtr pRegion
+#if XORG_VERSION_CURRENT < XORG_VERSION_NUMERIC(1,16,99,901,0)
+				   , RegionPtr pBSRegion
+#endif
+				   );
 
 /* amdgpu_present.c */
 Bool amdgpu_present_screen_init(ScreenPtr screen);
diff --git a/src/amdgpu_kms.c b/src/amdgpu_kms.c
index 4821e932f..90d0288af 100644
--- a/src/amdgpu_kms.c
+++ b/src/amdgpu_kms.c
@@ -1258,11 +1258,11 @@ static Bool AMDGPUCreateWindow_oneshot(WindowPtr pWin)
 }
 
 /* When the root window is mapped, set the initial modes */
-static void AMDGPUWindowExposures_oneshot(WindowPtr pWin, RegionPtr pRegion
+void AMDGPUWindowExposures_oneshot(WindowPtr pWin, RegionPtr pRegion
 #if XORG_VERSION_CURRENT < XORG_VERSION_NUMERIC(1,16,99,901,0)
-					  , RegionPtr pBSRegion
+				   , RegionPtr pBSRegion
 #endif
-	)
+				   )
 {
 	ScreenPtr pScreen = pWin->drawable.pScreen;
 	ScrnInfoPtr pScrn = xf86ScreenToScrn(pScreen);
diff --git a/src/drmmode_display.c b/src/drmmode_display.c
index 2cdea90ad..a041e8b67 100644
--- a/src/drmmode_display.c
+++ b/src/drmmode_display.c
@@ -779,6 +779,12 @@ drmmode_set_mode_major(xf86CrtcPtr crtc, DisplayModePtr mode,
 	drmModeModeInfo kmode;
 	uint32_t bo_handle;
 
+	/* The root window contents may be undefined before the WindowExposures
+	 * hook is called for it, so bail if we get here before that
+	 */
+	if (pScreen->WindowExposures == AMDGPUWindowExposures_oneshot)
+		return FALSE;
+
 	saved_mode = crtc->mode;
 	saved_x = crtc->x;
 	saved_y = crtc->y;
-- 
2.11.0