Date:   Mon, 27 Feb 2023 18:06:45 +0200
From:   Ville =?iso-8859-1?Q?Syrj=E4l=E4?= <ville.syrjala@linux.intel.com>
To:     Rob Clark <robdclark@gmail.com>
Cc:     Gerd Hoffmann <kraxel@redhat.com>,
        Rob Clark <robdclark@chromium.org>,
        Dmitry Osipenko <dmitry.osipenko@collabora.com>,
        open list <linux-kernel@vger.kernel.org>,
        dri-devel@lists.freedesktop.org,
        Gurchetan Singh <gurchetansingh@chromium.org>,
        Ryan Neph <ryanneph@chromium.org>,
        David Airlie <airlied@redhat.com>,
        "open list:VIRTIO GPU DRIVER" 
        <virtualization@lists.linux-foundation.org>
Subject: Re: [PATCH] drm/virtio: Add option to disable KMS support
Message-ID: <Y/zVFfSLoO5Fz/3D@intel.com>
References: <20230224180225.2477641-1-robdclark@gmail.com>
 <20230227063821.dg2gbjjwcekbxyzw@sirius.home.kraxel.org>
 <CAF6AEGsv1G7CPSkCPe3iHGB9JEO4iy+bTbkFLoitmx64U78RJw@mail.gmail.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=iso-8859-1
Content-Disposition: inline
Content-Transfer-Encoding: 8bit
In-Reply-To: <CAF6AEGsv1G7CPSkCPe3iHGB9JEO4iy+bTbkFLoitmx64U78RJw@mail.gmail.com>
Precedence: bulk

On Mon, Feb 27, 2023 at 07:40:11AM -0800, Rob Clark wrote:
> On Sun, Feb 26, 2023 at 10:38 PM Gerd Hoffmann <kraxel@redhat.com> wrote:
> >
> > On Fri, Feb 24, 2023 at 10:02:24AM -0800, Rob Clark wrote:
> > > From: Rob Clark <robdclark@chromium.org>
> > >
> > > Add a build option to disable modesetting support.  This is useful in
> > > cases where the guest only needs to use the GPU in a headless mode, or
> > > (such as in the CrOS usage) window surfaces are proxied to a host
> > > compositor.
> >
> > Why make that a compile time option?  There is a config option for the
> > number of scanouts (aka virtual displays) a device has.  Just set that
> > to zero (and fix the driver to not consider that configuration an
> > error).
> 
> The goal is to not advertise DRIVER_MODESET (and DRIVER_ATOMIC).. I
> guess that could be done based on whether there are any scanouts, but
> it would mean making the drm_driver struct non-const.

dev.driver_features is a thing.

-- 
Ville Syrj?l?
Intel