linux-kernel - [PATCH AUTOSEL 4.19 24/27] drm/ast: Fixed reboot test may cause system hanged

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Date:   Tue, 20 Aug 2019 09:42:10 -0400
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     "Y.C. Chen" <yc_chen@...eedtech.com>,
        Benjamin Herrenschmidt <benh@...nel.crashing.org>,
        Dave Airlie <airlied@...hat.com>,
        Sasha Levin <sashal@...nel.org>,
        dri-devel@...ts.freedesktop.org
Subject: [PATCH AUTOSEL 4.19 24/27] drm/ast: Fixed reboot test may cause system hanged

From: "Y.C. Chen" <yc_chen@...eedtech.com>

[ Upstream commit 05b439711f6ff8700e8660f97a1179650778b9cb ]

There is another thread still access standard VGA I/O while loading drm driver.
Disable standard VGA I/O decode to avoid this issue.

Signed-off-by: Y.C. Chen <yc_chen@...eedtech.com>
Reviewed-by: Benjamin Herrenschmidt <benh@...nel.crashing.org>
Signed-off-by: Dave Airlie <airlied@...hat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1523410059-18415-1-git-send-email-yc_chen@aspeedtech.com
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/gpu/drm/ast/ast_main.c | 5 ++++-
 drivers/gpu/drm/ast/ast_mode.c | 2 +-
 drivers/gpu/drm/ast/ast_post.c | 2 +-
 3 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/ast/ast_main.c b/drivers/gpu/drm/ast/ast_main.c
index 373700c05a00f..224fa1ef87ff9 100644
--- a/drivers/gpu/drm/ast/ast_main.c
+++ b/drivers/gpu/drm/ast/ast_main.c
@@ -131,8 +131,8 @@ static int ast_detect_chip(struct drm_device *dev, bool *need_post)
 
 
 	/* Enable extended register access */
-	ast_enable_mmio(dev);
 	ast_open_key(ast);
+	ast_enable_mmio(dev);
 
 	/* Find out whether P2A works or whether to use device-tree */
 	ast_detect_config_mode(dev, &scu_rev);
@@ -576,6 +576,9 @@ void ast_driver_unload(struct drm_device *dev)
 {
 	struct ast_private *ast = dev->dev_private;
 
+	/* enable standard VGA decode */
+	ast_set_index_reg(ast, AST_IO_CRTC_PORT, 0xa1, 0x04);
+
 	ast_release_firmware(dev);
 	kfree(ast->dp501_fw_addr);
 	ast_mode_fini(dev);
diff --git a/drivers/gpu/drm/ast/ast_mode.c b/drivers/gpu/drm/ast/ast_mode.c
index 8bb355d5d43d8..9d92d2d2fcfc7 100644
--- a/drivers/gpu/drm/ast/ast_mode.c
+++ b/drivers/gpu/drm/ast/ast_mode.c
@@ -600,7 +600,7 @@ static int ast_crtc_mode_set(struct drm_crtc *crtc,
 		return -EINVAL;
 	ast_open_key(ast);
 
-	ast_set_index_reg_mask(ast, AST_IO_CRTC_PORT, 0xa1, 0xff, 0x04);
+	ast_set_index_reg(ast, AST_IO_CRTC_PORT, 0xa1, 0x06);
 
 	ast_set_std_reg(crtc, adjusted_mode, &vbios_mode);
 	ast_set_crtc_reg(crtc, adjusted_mode, &vbios_mode);
diff --git a/drivers/gpu/drm/ast/ast_post.c b/drivers/gpu/drm/ast/ast_post.c
index f7d421359d564..c1d1ac51d1c20 100644
--- a/drivers/gpu/drm/ast/ast_post.c
+++ b/drivers/gpu/drm/ast/ast_post.c
@@ -46,7 +46,7 @@ void ast_enable_mmio(struct drm_device *dev)
 {
 	struct ast_private *ast = dev->dev_private;
 
-	ast_set_index_reg_mask(ast, AST_IO_CRTC_PORT, 0xa1, 0xff, 0x04);
+	ast_set_index_reg(ast, AST_IO_CRTC_PORT, 0xa1, 0x06);
 }
 
 
-- 
2.20.1