[PATCH 4.10 51/75] drm/ast: Fix test for VGA enabled

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

4.10-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Y.C. Chen <yc_chen@aspeedtech.com>

commit 905f21a49d388de3e99438235f3301cabf0c0ef4 upstream.

The test to see if VGA was already enabled is doing an unnecessary
second test from a register that may or may not have been initialized
to a valid value. Remove it.

Signed-off-by: Y.C. Chen <yc_chen@aspeedtech.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Acked-by: Joel Stanley <joel@jms.id.au>
Tested-by: Y.C. Chen <yc_chen@aspeedtech.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/gpu/drm/ast/ast_post.c |    8 ++------
 1 file changed, 2 insertions(+), 6 deletions(-)

--- a/drivers/gpu/drm/ast/ast_post.c
+++ b/drivers/gpu/drm/ast/ast_post.c
@@ -58,13 +58,9 @@ bool ast_is_vga_enabled(struct drm_devic
 		/* TODO 1180 */
 	} else {
 		ch = ast_io_read8(ast, AST_IO_VGA_ENABLE_PORT);
-		if (ch) {
-			ast_open_key(ast);
-			ch = ast_get_index_reg_mask(ast, AST_IO_CRTC_PORT, 0xb6, 0xff);
-			return ch & 0x04;
-		}
+		return !!(ch & 0x01);
 	}
-	return 0;
+	return false;
 }
 
 static const u8 extreginfo[] = { 0x0f, 0x04, 0x1c, 0xff };