[PATCH] drm/ast: Fixed reboot test may cause system hanged

[Benjamin Herrenschmidt]

On Wed, 2018-04-11 at 09:27 +0800, Y.C. Chen wrote:
> From: "Y.C. Chen" <yc_chen at aspeedtech.com>
> 
> There is another thread still access standard VGA I/O while loading drm driver.
> Disable standard VGA I/O decode to avoid this issue.

Jeremy, Joel, can we regression test that on our systems ?

> Signed-off-by: Y.C. Chen <yc_chen at aspeedtech.com>
> ---
>  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 dac3558..82a2687 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 831b733..9d637b4 100644
> --- a/drivers/gpu/drm/ast/ast_mode.c
> +++ b/drivers/gpu/drm/ast/ast_mode.c
> @@ -599,7 +599,7 @@ 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 f7d4213..c1d1ac5 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);
>  }
>  
>