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Message-ID: <1536571118.4810.38.camel@collabora.com>
Subject: Re: [PATCH v7] Add udmabuf misc device
From:   Gert Wollny <gert.wollny@collabora.com>
To:     Gerd Hoffmann <kraxel@redhat.com>
Cc:     linux-kernel@vger.kernel.org, David Airlie <airlied@linux.ie>,
        Tomeu Vizoso <tomeu.vizoso@collabora.com>,
        Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
        Daniel Vetter <daniel@ffwll.ch>
Date:   Mon, 10 Sep 2018 11:18:38 +0200
In-Reply-To: <20180910083731.o4rryvermyighbtp@sirius.home.kraxel.org>
References: <1536491489.4810.22.camel@collabora.com>
         <20180910083731.o4rryvermyighbtp@sirius.home.kraxel.org>
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Am Montag, den 10.09.2018, 10:37 +0200 schrieb Gerd Hoffmann:
... 

> > The other question is of course, why did dma_buf_export fail for me
> > ...
> 
> What exactly did you try?

I ran 

qemu-system-x86_64 -enable-kvm -smp 5 -M q35 -m 8G \
    -drive format=raw,file=ubuntu.raw,if=virtio   \
    -net nic,model=virtio  -net user,hostfwd=tcp::2224-:22  \
    -vga virtio

ubuntu.raw = Ubuntu 18.04 (bionic) + 4.17 kernel (from Ubuntu cosmic). 

The VM boots up to a certain point, the last line from the boot log is
varying, as far as I can see it is a few lines after virtio_blk detects
the disks.  

When I add '-display sdl' the Xsession freezes. I was still able to log
in remotely and kill -9 qemu, then X11 became usable again. 

In all cases I get on the host: 
  qemu-system-x86_64: info: udmabuf: init ok

and there it stays, certainly because of the kernel bug reported. 

Best, 
Gert