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From:   John Stultz <john.stultz@linaro.org>
Date:   Fri, 15 Mar 2019 13:13:08 -0700
Message-ID: <CALAqxLUjSZHBXsT0c-KTra4zLFxCYDmYHTJswk5OckrUbd=ykg@mail.gmail.com>
Subject: Re: [RFC][PATCH 5/5 v2] kselftests: Add dma-heap test
To:     Laura Abbott <labbott@redhat.com>
Cc:     Benjamin Gaignard <benjamin.gaignard@linaro.org>,
        lkml <linux-kernel@vger.kernel.org>,
        Greg KH <gregkh@linuxfoundation.org>,
        Sumit Semwal <sumit.semwal@linaro.org>,
        Liam Mark <lmark@codeaurora.org>,
        Brian Starkey <Brian.Starkey@arm.com>,
        "Andrew F . Davis" <afd@ti.com>, Chenbo Feng <fengc@google.com>,
        Alistair Strachan <astrachan@google.com>,
        ML dri-devel <dri-devel@lists.freedesktop.org>
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On Fri, Mar 15, 2019 at 1:07 PM Laura Abbott <labbott@redhat.com> wrote:
>
> On 3/6/19 9:01 AM, John Stultz wrote:
> > On Wed, Mar 6, 2019 at 8:14 AM Benjamin Gaignard
> > <benjamin.gaignard@linaro.org> wrote:
> >> Le mar. 5 mars 2019 =C3=A0 21:54, John Stultz <john.stultz@linaro.org>=
 a =C3=A9crit :
> >>> +
> >>> +       printf("Allocating 1 MEG\n");
> >>> +       ret =3D dmabuf_heap_alloc(heap_fd, ONE_MEG, 0, &dmabuf_fd);
> >>> +       if (ret)
> >>> +               goto out;
> >>> +
> >>> +       /* DO SOMETHING WITH THE DMABUF HERE? */
> >>
> >> You can do a call to mmap and write a pattern in the buffer.
> >
> > Yea. I can also do some invalid allocations to make sure things fail pr=
operly.
> >
> > But I was talking a bit w/ Sumit about the lack of any general dmabuf
> > tests, and am curious if we need to have a importer device driver that
> > can validate its a real dmabuf and exercise more of the dmabuf ops.
> >
> > thanks
> > -john
> >
>
> There's the vgem driver in drm. I did some work to clean that
> up so it could take an import af33a9190d02 ("drm/vgem: Enable dmabuf impo=
rt
> interfaces") . I mostly used it for private tests and never ended
> up upstreaming any of the tests.

Thanks for the poitner, I'll check that out as well!  Also, if you
still have them around, I'd be interested in checking out the tests to
try to get something integrated into kselftest.

Talking with Brian yesterday, there was some thought that we should
try to put together some sort of example dmabuf pipeline that isn't
hardware dependent and can be used to demonstrate the usage model as
well as validate the frameworks and maybe even benchmark some of the
ideas floating around right now.  So suggestions here would be
welcome!

thanks
-john