From 64e52dc156715cd15e1741bd8fec064f2e4c8eda Mon Sep 17 00:00:00 2001
From: Zack Rusin <zackr@vmware.com>
Date: Fri, 18 Mar 2022 13:43:29 -0400
Subject: drm/vmwgfx: Fix mob cursor allocation race
Git-commit: ab709795e38637320fea9fdc8e06b64f670b58ee
Patch-mainline: v5.19-rc1
References: jsc#PED-1166 jsc#PED-1168 jsc#PED-1170 jsc#PED-1218 jsc#PED-1220 jsc#PED-1222 jsc#PED-1223 jsc#PED-1225
Writes to SVGA_REG_CURSOR_MOBID did not wait for the buffers to be fully
populated. This sometimes results in the device not being aware of
the buffer when the cursor mob register was written.
Properly wait for the buffer to be fully populated before setting it
as a cursor mob.
Signed-off-by: Zack Rusin <zackr@vmware.com>
Fixes: 485d98d472d5 ("drm/vmwgfx: Add support for CursorMob and CursorBypass 4")
Reviewed-by: Martin Krastev <krastevm@vmware.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220318174332.440068-3-zack@kde.org
Acked-by: Patrik Jakobsson <pjakobsson@suse.de>
---
drivers/gpu/drm/vmwgfx/vmwgfx_kms.c | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_kms.c b/drivers/gpu/drm/vmwgfx/vmwgfx_kms.c
index af252210ef84..7a23f252d212 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_kms.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_kms.c
@@ -602,6 +602,14 @@ vmw_du_cursor_plane_prepare_fb(struct drm_plane *plane,
ret = ttm_bo_kmap(cm_bo, 0, PFN_UP(size), &vps->cm_map);
+ /*
+ * We just want to try to get mob bind to finish
+ * so that the first write to SVGA_REG_CURSOR_MOBID
+ * is done with a buffer that the device has already
+ * seen
+ */
+ (void) ttm_bo_wait(cm_bo, false, false);
+
ttm_bo_unreserve(cm_bo);
if (unlikely(ret != 0)) {
--
2.38.1