[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 at suse.de>
> Fixes: bad09da6deab ("drm/ast: Fixed vram size incorrect issue on
> POWER")
> Cc: Joel Stanley <joel at jms.id.au>
> Cc: Y.C. Chen <yc_chen at aspeedtech.com>

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

> Cc: Dave Airlie <airlied at redhat.com>
> Cc: Thomas Zimmermann <tzimmermann at suse.de>
> Cc: Gerd Hoffmann <kraxel at redhat.com>
> Cc: Daniel Vetter <daniel.vetter at ffwll.ch>
> Cc: Sam Ravnborg <sam at ravnborg.org>
> Cc: Emil Velikov <emil.l.velikov at gmail.com>
> Cc: "Y.C. Chen" <yc_chen at aspeedtech.com>
> Cc: <stable at 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;