[PATCH 5/6] drm/ast: Initialize DRAM type before posting GPU

[PATCH 5/6] drm/ast: Initialize DRAM type before posting GPU

[Thomas Zimmermann]

Posting the GPU requires the correct DRAM type to be stored in
struct ast_private. Therefore first initialize the DRAM info and
then post the GPU. This restores the original order of instructions
in this function.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Fixes: bad09da6deab ("drm/ast: Fixed vram size incorrect issue on POWER")
Cc: Joel Stanley <joel@jms.id.au>
Cc: Y.C. Chen <yc_chen@aspeedtech.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Dave Airlie <airlied@redhat.com>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Emil Velikov <emil.l.velikov@gmail.com>
Cc: "Y.C. Chen" <yc_chen@aspeedtech.com>
Cc: <stable@vger.kernel.org> # v4.11+
---
 drivers/gpu/drm/ast/ast_main.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/ast/ast_main.c b/drivers/gpu/drm/ast/ast_main.c
index b162cc82204d..87e5baded2a7 100644
--- a/drivers/gpu/drm/ast/ast_main.c
+++ b/drivers/gpu/drm/ast/ast_main.c
@@ -418,15 +418,15 @@ int ast_driver_load(struct drm_device *dev, unsigned long flags)
 
 	ast_detect_chip(dev, &need_post);
 
-	if (need_post)
-		ast_post_gpu(dev);
-
 	ret = ast_get_dram_info(dev);
 	if (ret)
 		goto out_free;
 	drm_info(dev, "dram MCLK=%u Mhz type=%d bus_width=%d\n",
 		 ast->mclk, ast->dram_type, ast->dram_bus_width);
 
+	if (need_post)
+		ast_post_gpu(dev);
+
 	ret = ast_mm_init(ast);
 	if (ret)
 		goto out_free;
-- 
2.27.0

Re: [PATCH 5/6] drm/ast: Initialize DRAM type before posting GPU

[Benjamin Herrenschmidt]

On Wed, 2020-07-08 at 09:49 +0200, Thomas Zimmermann wrote:
> Posting the GPU requires the correct DRAM type to be stored in
> struct ast_private. Therefore first initialize the DRAM info and
> then post the GPU. This restores the original order of instructions
> in this function.

I no longer have access to the relevant test POWER systems,
however the patch looks good to me.

> Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
> Fixes: bad09da6deab ("drm/ast: Fixed vram size incorrect issue on
> POWER")
> Cc: Joel Stanley <joel@jms.id.au>
> Cc: Y.C. Chen <yc_chen@aspeedtech.com>

Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

> Cc: Dave Airlie <airlied@redhat.com>
> Cc: Thomas Zimmermann <tzimmermann@suse.de>
> Cc: Gerd Hoffmann <kraxel@redhat.com>
> Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
> Cc: Sam Ravnborg <sam@ravnborg.org>
> Cc: Emil Velikov <emil.l.velikov@gmail.com>
> Cc: "Y.C. Chen" <yc_chen@aspeedtech.com>
> Cc: <stable@vger.kernel.org> # v4.11+
> ---
>  drivers/gpu/drm/ast/ast_main.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/gpu/drm/ast/ast_main.c
> b/drivers/gpu/drm/ast/ast_main.c
> index b162cc82204d..87e5baded2a7 100644
> --- a/drivers/gpu/drm/ast/ast_main.c
> +++ b/drivers/gpu/drm/ast/ast_main.c
> @@ -418,15 +418,15 @@ int ast_driver_load(struct drm_device *dev,
> unsigned long flags)
>  
>  	ast_detect_chip(dev, &need_post);
>  
> -	if (need_post)
> -		ast_post_gpu(dev);
> -
>  	ret = ast_get_dram_info(dev);
>  	if (ret)
>  		goto out_free;
>  	drm_info(dev, "dram MCLK=%u Mhz type=%d bus_width=%d\n",
>  		 ast->mclk, ast->dram_type, ast->dram_bus_width);
>  
> +	if (need_post)
> +		ast_post_gpu(dev);
> +
>  	ret = ast_mm_init(ast);
>  	if (ret)
>  		goto out_free;