Subject: Re: [PATCH v3] drm: omapdrm: Export correct scatterlist for TILER
 backed BOs
To:     Ivaylo Dimitrov <ivo.g.dimitrov.75@gmail.com>
Cc:     matthijsvanduin@gmail.com, airlied@linux.ie, daniel@ffwll.ch,
        linux-kernel@vger.kernel.org, linux-omap@vger.kernel.org,
        merlijn@wizzup.org, philipp@uvos.xyz,
        laurent.pinchart@ideasonboard.com
References: <3e9307e5-1f03-9854-2b2b-859173e8f2ae@gmail.com>
 <1637309180-31032-1-git-send-email-ivo.g.dimitrov.75@gmail.com>
From:   Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
Message-ID: <56fc4b66-c7c6-586e-229d-6850d561c6f7@ideasonboard.com>
Date:   Thu, 2 Dec 2021 11:13:13 +0200
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Hi,

On 19/11/2021 10:06, Ivaylo Dimitrov wrote:
> Memory of BOs backed by TILER is not contiguous, but omap_gem_map_dma_buf()
> exports it like it is. This leads to (possibly) invalid memory accesses if
> another device imports such a BO.
> 
> Fix that by providing sg that correctly describes TILER memory layout.
> Align TILER allocations to page, so importer to be able to correctly set
> its MMU if have one. Set export size accounting for the alignment. Also,
> make sure to destroy sg on unpin, as it is no longer valid.
> 
> Tested on Motorola Droid4 by using GPU (sgx540) to render.
> 
> Suggested-by: Matthijs van Duin <matthijsvanduin@gmail.com>
> Signed-off-by: Ivaylo Dimitrov <ivo.g.dimitrov.75@gmail.com>
> ---
>   drivers/gpu/drm/omapdrm/omap_gem.c        | 79 ++++++++++++++++++++++++++++++-
>   drivers/gpu/drm/omapdrm/omap_gem.h        |  2 +
>   drivers/gpu/drm/omapdrm/omap_gem_dmabuf.c | 34 ++-----------
>   3 files changed, 85 insertions(+), 30 deletions(-)

I'll pick this to my work branch which I use every day, and let it be 
there for a few days. If I don't see any issues, I'll push to drm-misc-next.

  Tomi