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Date:   Thu, 23 Jun 2022 10:13:26 +0300
From:   Pekka Paalanen <ppaalanen@gmail.com>
To:     Christian =?UTF-8?B?S8O2bmln?= <christian.koenig@amd.com>
Cc:     Daniel Stone <daniel@fooishbar.org>,
        Nicolas Dufresne <nicolas@ndufresne.ca>,
        Daniel Vetter <daniel@ffwll.ch>,
        "Sharma, Shashank" <Shashank.Sharma@amd.com>,
        lkml <linux-kernel@vger.kernel.org>,
        dri-devel <dri-devel@lists.freedesktop.org>,
        linaro-mm-sig@lists.linaro.org,
        Sumit Semwal <sumit.semwal@linaro.org>,
        linux-media <linux-media@vger.kernel.org>
Subject: Re: DMA-buf and uncached system memory
Message-ID: <20220623101326.18beeab3@eldfell>
In-Reply-To: <c6e65ee1-531e-d72c-a6a6-da7149e34f18@amd.com>
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On Thu, 23 Jun 2022 08:59:41 +0200
Christian K=C3=B6nig <christian.koenig@amd.com> wrote:

> The exporter isn't doing anything wrong here. DMA-buf are supposed to be=
=20
> CPU cached and can also be cache hot.

Hi,

what is that statement based on?

Were the (mandatory for CPU access) cpu_access_begin/end functions &
ioctls not supposed to ensure that CPU cache is up-to-date / CPU cache
is fully flushed out?


Thanks,
pq

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