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From:   Arnd Bergmann <arnd@kernel.org>
Date:   Tue, 15 Jun 2021 10:39:50 +0200
Message-ID: <CAK8P3a2vgaOLtMBR84LCmsu8NA7b7bPK2jJoiqTxvgTzX7Lobw@mail.gmail.com>
Subject: Re: [PATCH v3 7/8] media: subdev: fix compat_ioctl32
To:     Hans Verkuil <hverkuil-cisco@xs4all.nl>
Cc:     Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
        Mauro Carvalho Chehab <mchehab@kernel.org>,
        "Lad, Prabhakar" <prabhakar.csengg@gmail.com>,
        Eduardo Valentin <edubezval@gmail.com>,
        Sakari Ailus <sakari.ailus@linux.intel.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Vaibhav Gupta <vaibhavgupta40@gmail.com>,
        Liu Shixin <liushixin2@huawei.com>,
        Jacopo Mondi <jacopo+renesas@jmondi.org>,
        Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Linux Media Mailing List <linux-media@vger.kernel.org>,
        linux-staging@lists.linux.dev
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On Tue, Jun 15, 2021 at 10:27 AM Hans Verkuil <hverkuil-cisco@xs4all.nl> wrote:
> On 14/06/2021 19:18, Laurent Pinchart wrote:

> >
> > Should we drop v4l2_subdev_core_ops.compat_ioctl32 and call
> > v4l2_subdev_core_ops.ioctl from subdev_do_compat_ioctl32() ? New drivers
> > should design custom ioctls in a way that doesn't require compat code.
>
> I agree, we can drop it completely.

I agree about new drivers defining their ioctls in a compatible way,
though Ideally
I'd say subdev drivers should not use custom ioctls at all. There are
two other drivers
that define private subdev ioctls and that lack a working compat handler:

- the omap3 isp driver would not work in compat mode, though I don't think there
  are any 64-bit SoCs using this hardware. The Sitara AM6 and J72 SoCs
  are the only chips in that family at the moment, but these don't
seem to include
  any image processor.

- The Intel Atom ISP driver has a broken compat ioctl handler that I remove
  in this series, but the  v4l2_subdev_core_ops->compat_ioctl32 callback
  would be the correct place to hook these up if they do not get fixed.

> I'll skip this patch, but I'll take the other 7 patches and make a v3 PR with
> updated Reviewed-by tags from Laurent.

Thanks!

        Arnd