[PATCH v3 8/8] drm/vmwgfx: Fix display register usage for some older configs

[Zack Rusin]

We can't be setting the display_id register to an invalid value
because that makes our device reset the fb which causes nasty
flicker (due to destruction and creation of a new fb).
Also we can't be using the BITS_PER_PIXEL register if the
8BIT_EMULATION is not supported.

Signed-off-by: Zack Rusin <zackr at vmware.com>
Reviewed-by: Martin Krastev <krastevm at vmware.com>
Reviewed-by: Roland Scheidegger <sroland at vmware.com>
---
 drivers/gpu/drm/vmwgfx/vmwgfx_kms.c | 3 ++-
 drivers/gpu/drm/vmwgfx/vmwgfx_ldu.c | 1 -
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_kms.c b/drivers/gpu/drm/vmwgfx/vmwgfx_kms.c
index f2a9188d0b7d..9a89f658e501 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_kms.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_kms.c
@@ -1875,7 +1875,8 @@ int vmw_kms_write_svga(struct vmw_private *vmw_priv,
 		vmw_fifo_mem_write(vmw_priv, SVGA_FIFO_PITCHLOCK, pitch);
 	vmw_write(vmw_priv, SVGA_REG_WIDTH, width);
 	vmw_write(vmw_priv, SVGA_REG_HEIGHT, height);
-	vmw_write(vmw_priv, SVGA_REG_BITS_PER_PIXEL, bpp);
+	if ((vmw_priv->capabilities & SVGA_CAP_8BIT_EMULATION) != 0)
+		vmw_write(vmw_priv, SVGA_REG_BITS_PER_PIXEL, bpp);
 
 	if (vmw_read(vmw_priv, SVGA_REG_DEPTH) != depth) {
 		DRM_ERROR("Invalid depth %u for %u bpp, host expects %u\n",
diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_ldu.c b/drivers/gpu/drm/vmwgfx/vmwgfx_ldu.c
index ac806ae78894..9a9508edbc9e 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_ldu.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_ldu.c
@@ -125,7 +125,6 @@ static int vmw_ldu_commit_list(struct vmw_private *dev_priv)
 		vmw_write(dev_priv, SVGA_REG_DISPLAY_POSITION_Y, crtc->y);
 		vmw_write(dev_priv, SVGA_REG_DISPLAY_WIDTH, crtc->mode.hdisplay);
 		vmw_write(dev_priv, SVGA_REG_DISPLAY_HEIGHT, crtc->mode.vdisplay);
-		vmw_write(dev_priv, SVGA_REG_DISPLAY_ID, SVGA_ID_INVALID);
 
 		i++;
 	}
-- 
2.27.0