drm/ast: Initialize ASTDP in ast_post_gpu()

Remove the call to ast_dp_launch() from ast_detect_tx_chip() and
perform it unconditionally in ast_post_gpu().

Also add error handling: the detection code apparently used
ast_dp_launch() to test for a working ASTDP, falling back to VGA on
errors. As the VBIOS reports ASTDP, silently ignoring errors is
questionable behavior. With the refactoring, failing to initialize
the ASTDP will also fail probing the driver.

Signed-off-by: Thomas Zimmermann <[email protected]>
Reviewed-by: Jocelyn Falempe <[email protected]>
Link: https://patchwork.freedesktop.org/patch/msgid/[email protected]

1 files changed, 13 insertions, 6 deletions

diff --git a/drivers/gpu/drm/ast/ast_main.c b/drivers/gpu/drm/ast/ast_main.c
index 456230bef273..474eb255b325 100644
--- a/drivers/gpu/drm/ast/ast_main.c
+++ b/drivers/gpu/drm/ast/ast_main.c
@@ -138,10 +138,7 @@ static void ast_detect_tx_chip(struct ast_device *ast, bool need_post)
 	} else if (IS_AST_GEN7(ast)) {
 		if (ast_get_index_reg_mask(ast, AST_IO_VGACRI, 0xd1, AST_IO_VGACRD1_TX_TYPE_MASK) ==
 		    AST_IO_VGACRD1_TX_ASTDP) {
-			int ret = ast_dp_launch(ast);
-
-			if (!ret)
-				ast->tx_chip = AST_TX_ASTDP;
+			ast->tx_chip = AST_TX_ASTDP;
 		}
 	}
 
@@ -297,8 +294,18 @@ struct drm_device *ast_device_create(struct pci_dev *pdev,
 		 ast->mclk, ast->dram_type, ast->dram_bus_width);
 
 	ast_detect_tx_chip(ast, need_post);
-	if (need_post)
-		ast_post_gpu(ast);
+	switch (ast->tx_chip) {
+	case AST_TX_ASTDP:
+		ret = ast_post_gpu(ast);
+		break;
+	default:
+		ret = 0;
+		if (need_post)
+			ret = ast_post_gpu(ast);
+		break;
+	}
+	if (ret)
+		return ERR_PTR(ret);
 
 	ret = ast_mm_init(ast);
 	if (ret)