From b620fb89c9ebaa76e7418da7f48d1cdf7178ab82 Mon Sep 17 00:00:00 2001
From: Zack Rusin <zackr@vmware.com>
Date: Wed, 2 Mar 2022 10:24:20 -0500
Subject: drm/vmwgfx: Cleanup multimon initialization code
Git-commit: bb30d8d8c1b0002712f112c519c9caf4fdf8c9d1
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

The results of the legacy display unit initialization were being silently
ignored. Unifying the selection of number of display units based
on whether the underlying device supports multimon makes it easier
to add error checking to all paths.

This makes the driver report the errors in ldu initialization paths
and try to recover from them.

Signed-off-by: Zack Rusin <zackr@vmware.com>
Reviewed-by: Martin Krastev <krastevm@vmware.com>
Reviewed-by: Maaz Mombasawala <mombasawalam@vmware.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220302152426.885214-3-zack@kde.org
Acked-by: Patrik Jakobsson <pjakobsson@suse.de>
---
 drivers/gpu/drm/vmwgfx/vmwgfx_ldu.c | 18 ++++++++----------
 1 file changed, 8 insertions(+), 10 deletions(-)

diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_ldu.c b/drivers/gpu/drm/vmwgfx/vmwgfx_ldu.c
index 643c1608ddfd..e4347faccee0 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_ldu.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_ldu.c
@@ -492,6 +492,8 @@ int vmw_kms_ldu_init_display(struct vmw_private *dev_priv)
 {
 	struct drm_device *dev = &dev_priv->drm;
 	int i, ret;
+	int num_display_units = (dev_priv->capabilities & SVGA_CAP_MULTIMON) ?
+					VMWGFX_NUM_DISPLAY_UNITS : 1;
 
 	if (unlikely(dev_priv->ldu_priv)) {
 		return -EINVAL;
@@ -506,21 +508,17 @@ int vmw_kms_ldu_init_display(struct vmw_private *dev_priv)
 	dev_priv->ldu_priv->last_num_active = 0;
 	dev_priv->ldu_priv->fb = NULL;
 
-	/* for old hardware without multimon only enable one display */
-	if (dev_priv->capabilities & SVGA_CAP_MULTIMON)
-		ret = drm_vblank_init(dev, VMWGFX_NUM_DISPLAY_UNITS);
-	else
-		ret = drm_vblank_init(dev, 1);
+	ret = drm_vblank_init(dev, num_display_units);
 	if (ret != 0)
 		goto err_free;
 
 	vmw_kms_create_implicit_placement_property(dev_priv);
 
-	if (dev_priv->capabilities & SVGA_CAP_MULTIMON)
-		for (i = 0; i < VMWGFX_NUM_DISPLAY_UNITS; ++i)
-			vmw_ldu_init(dev_priv, i);
-	else
-		vmw_ldu_init(dev_priv, 0);
+	for (i = 0; i < num_display_units; ++i) {
+		ret = vmw_ldu_init(dev_priv, i);
+		if (ret != 0)
+			goto err_free;
+	}
 
 	dev_priv->active_display_unit = vmw_du_legacy;
 
-- 
2.38.1