[PATCH] drm/ast: Fix black screen after resume

[Jammy Huang]

Suspend will disable pcie device. Thus, resume should do full hw
initialization again.
Add some APIs to ast_drm_thaw() before ast_post_gpu() to fix the issue.

Fixes: 5b71707dd13 ("drm/ast: Enable and unlock device access early during init")
Signed-off-by: Jammy Huang <jammy_huang at aspeedtech.com>
---
 drivers/gpu/drm/ast/ast_drv.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/gpu/drm/ast/ast_drv.c b/drivers/gpu/drm/ast/ast_drv.c
index f8c49ba68e78..45a9c7bf49c8 100644
--- a/drivers/gpu/drm/ast/ast_drv.c
+++ b/drivers/gpu/drm/ast/ast_drv.c
@@ -391,6 +391,11 @@ static int ast_drm_freeze(struct drm_device *dev)
 
 static int ast_drm_thaw(struct drm_device *dev)
 {
+	struct ast_device *ast = to_ast_device(dev);
+
+	ast_enable_vga(ioregs);
+	ast_open_key(ioregs);
+	ast_enable_mmio(dev, ioregs);
 	ast_post_gpu(dev);
 
 	return drm_mode_config_helper_resume(dev);

base-commit: e9d22f7a6655941fc8b2b942ed354ec780936b3e
prerequisite-patch-id: a03a33902f33bcc38091e2cdce9d79f630464c30
prerequisite-patch-id: 505779a1e2094f2ee2f2a55ad44aac5cd1d5342f
-- 
2.25.1