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Date:   Wed, 20 Sep 2023 21:41:17 +0200
From:   Sebastian Reichel <sebastian.reichel@collabora.com>
To:     "H. Nikolaus Schaller" <hns@goldelico.com>
Cc:     Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>, tony@atomide.com,
        David Airlie <airlied@gmail.com>,
        Daniel Vetter <daniel@ffwll.ch>,
        Douglas Anderson <dianders@chromium.org>,
        Uwe =?utf-8?Q?Kleine-K=C3=B6nig?= 
        <u.kleine-koenig@pengutronix.de>,
        Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
        Arnd Bergmann <arnd@arndb.de>, dri-devel@lists.freedesktop.org,
        linux-kernel@vger.kernel.org, linux-omap@vger.kernel.org,
        letux-kernel@openphoenux.org, kernel@pyra-handheld.com
Subject: Re: [PATCH] omap: dsi: do not WARN on detach if dsidev was never
 attached
Message-ID: <20230920194117.ghllpy7ubghakdrv@mercury.elektranox.org>
References: <929c46beecf77f2ebfa9f8c9b1c09f6ec610c31a.1695130648.git.hns@goldelico.com>
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Hi,

On Tue, Sep 19, 2023 at 03:37:28PM +0200, H. Nikolaus Schaller wrote:
> dsi_init_output() called by dsi_probe() may fail. In that
> case mipi_dsi_host_unregister() is called which may call
> omap_dsi_host_detach() with uninitialized dsi->dsidev
> because omap_dsi_host_attach() was never called before.
>=20
> This happens if the panel driver asks for an EPROBE_DEFER.
>=20
> So let's suppress the WARN() in this special case.

=2E..

> Signed-off-by: H. Nikolaus Schaller <hns@goldelico.com>
> ---

Reviewed-by: Sebastian Reichel <sebastian.reichel@collabora.com>

-- Sebastian

>  drivers/gpu/drm/omapdrm/dss/dsi.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>=20
> diff --git a/drivers/gpu/drm/omapdrm/dss/dsi.c b/drivers/gpu/drm/omapdrm/=
dss/dsi.c
> index ea63c64d3a1ab..c37eb6b1b9a39 100644
> --- a/drivers/gpu/drm/omapdrm/dss/dsi.c
> +++ b/drivers/gpu/drm/omapdrm/dss/dsi.c
> @@ -4411,7 +4411,7 @@ static int omap_dsi_host_detach(struct mipi_dsi_hos=
t *host,
>  {
>  	struct dsi_data *dsi =3D host_to_omap(host);
> =20
> -	if (WARN_ON(dsi->dsidev !=3D client))
> +	if (!dsi->dsidev || WARN_ON(dsi->dsidev !=3D client))
>  		return -EINVAL;
> =20
>  	cancel_delayed_work_sync(&dsi->dsi_disable_work);
> --=20
> 2.42.0
>=20

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