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Subject: Re: [PATCH v2 01/11] dma-buf/sync_file: de-stage sync_file
To: Gustavo Padovan <gustavo@padovan.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>
References: <1453901439-19467-1-git-send-email-gustavo@padovan.org>
 <1453901439-19467-2-git-send-email-gustavo@padovan.org>
Cc: linux-kernel@vger.kernel.org, devel@driverdev.osuosl.org,
        dri-devel@lists.freedesktop.org, Daniel Stone <daniels@collabora.com>,
        =?UTF-8?Q?Arve_Hj=c3=b8nnev=c3=a5g?= <arve@android.com>,
        Riley Andrews <riandrews@android.com>,
        Daniel Vetter <daniel.vetter@ffwll.ch>,
        Rob Clark <robdclark@gmail.com>, Greg Hackmann <ghackmann@google.com>,
        John Harrison <John.C.Harrison@Intel.com>,
        Gustavo Padovan <gustavo.padovan@collabora.co.uk>
From: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Message-ID: <56A8D4A7.1070409@linux.intel.com>
Date: Wed, 27 Jan 2016 15:31:03 +0100
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Hey,

Op 27-01-16 om 14:30 schreef Gustavo Padovan:
> From: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
>
> sync_file is useful to connect one or more fences to the file. The file is
> used by userspace to track fences.
>
> Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
>
Is there a value in keeping the abi unchanged?
If not, then Documentation/ioctl/botching-up-ioctls.txt is worth a read.

Looking at the patch, it seems you kept SYNC_IOC_WAIT, won't it be better to remove it, and only support waiting with polling?
The code for polling should already work.

It's very unclear what format @driver_data has. I kept it for compatibility with android, but it's not clear to me how a userspace consumer would print it.
Is there a usecase for this, or could it be removed from fence and sync_file?

~Maarten