linux-kernel - Re: [Freedreno] [PATCH 5/5] drm/msm: deprecate MSM_BO_UNCACHED (map as writecombine instead)

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Message-ID: <20210502195658.ijhfpuadarlykduw@cosmicpenguin.net>
Date:   Sun, 2 May 2021 13:56:58 -0600
From:   Jordan Crouse <jordan@...micpenguin.net>
To:     Jonathan Marek <jonathan@...ek.ca>
Cc:     freedreno@...ts.freedesktop.org, David Airlie <airlied@...ux.ie>,
        "open list:DRM DRIVER FOR MSM ADRENO GPU" 
        <linux-arm-msm@...r.kernel.org>,
        open list <linux-kernel@...r.kernel.org>,
        "open list:DRM DRIVER FOR MSM ADRENO GPU" 
        <dri-devel@...ts.freedesktop.org>, Rob Clark <robdclark@...il.com>,
        Daniel Vetter <daniel@...ll.ch>, Sean Paul <sean@...rly.run>
Subject: Re: [Freedreno] [PATCH 5/5] drm/msm: deprecate MSM_BO_UNCACHED (map
 as writecombine instead)

On Fri, Apr 23, 2021 at 03:08:21PM -0400, Jonathan Marek wrote:
> There shouldn't be any reason to ever use uncached over writecombine,
> so just use writecombine for MSM_BO_UNCACHED.

Extremely correct.

> 
> Note: userspace never used MSM_BO_UNCACHED anyway
> 

Acked-by: Jordan Crouse <jordan@...micpenguin.net>

> Signed-off-by: Jonathan Marek <jonathan@...ek.ca>
> ---
>  drivers/gpu/drm/msm/msm_gem.c | 4 +---
>  include/uapi/drm/msm_drm.h    | 2 +-
>  2 files changed, 2 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/gpu/drm/msm/msm_gem.c b/drivers/gpu/drm/msm/msm_gem.c
> index 2e92e80009c8..56bca9178253 100644
> --- a/drivers/gpu/drm/msm/msm_gem.c
> +++ b/drivers/gpu/drm/msm/msm_gem.c
> @@ -201,10 +201,8 @@ void msm_gem_put_pages(struct drm_gem_object *obj)
>  
>  static pgprot_t msm_gem_pgprot(struct msm_gem_object *msm_obj, pgprot_t prot)
>  {
> -	if (msm_obj->flags & MSM_BO_WC)
> +	if (msm_obj->flags & (MSM_BO_WC|MSM_BO_UNCACHED))
>  		return pgprot_writecombine(prot);
> -	if (msm_obj->flags & MSM_BO_UNCACHED)
> -		return pgprot_noncached(prot);
>  	return prot;
>  }
>  
> diff --git a/include/uapi/drm/msm_drm.h b/include/uapi/drm/msm_drm.h
> index a92d90a6d96f..f075851021c3 100644
> --- a/include/uapi/drm/msm_drm.h
> +++ b/include/uapi/drm/msm_drm.h
> @@ -94,7 +94,7 @@ struct drm_msm_param {
>  /* cache modes */
>  #define MSM_BO_CACHED        0x00010000
>  #define MSM_BO_WC            0x00020000
> -#define MSM_BO_UNCACHED      0x00040000
> +#define MSM_BO_UNCACHED      0x00040000 /* deprecated, use MSM_BO_WC */
>  #define MSM_BO_CACHED_COHERENT 0x080000
>  
>  #define MSM_BO_FLAGS         (MSM_BO_SCANOUT | \
> -- 
> 2.26.1
> 
> _______________________________________________
> Freedreno mailing list
> Freedreno@...ts.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/freedreno

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