Re: [PATCH] drm/rcar-du: Fix error check when retrieving crtc state

[Sean Paul <sean@poorly.run>]

On Tue, Jun 18, 2019 at 10:26:52AM +0300, Laurent Pinchart wrote:
> Hi Sean,
> 
> Thank you for the patch.
> 
> On Mon, Jun 17, 2019 at 02:15:42PM -0400, Sean Paul wrote:
> > From: Sean Paul <seanpaul@chromium.org>
> > 
> > drm_atomic_get_crtc_state() returns an error pointer when it fails, so
> > the null check is doing nothing here.
> > 
> > Credit to 0-day/Dan Carpenter for reporting this.
> > 
> > Fixes: 6f3b62781bbd ("drm: Convert connector_helper_funcs->atomic_check to accept drm_atomic_state")
> > Cc: Daniel Vetter <daniel@ffwll.ch>
> > Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
> > Cc: Jani Nikula <jani.nikula@linux.intel.com>
> > Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
> > Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
> > Cc: Ben Skeggs <bskeggs@redhat.com>
> > Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> > Cc: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
> > Cc: Eric Anholt <eric@anholt.net>
> > Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com> [for rcar lvds]
> > Cc: Sean Paul <seanpaul@chromium.org>
> > Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
> > Cc: Maxime Ripard <maxime.ripard@bootlin.com>
> > Cc: Sean Paul <sean@poorly.run>
> > Cc: David Airlie <airlied@linux.ie>
> > Cc: Lyude Paul <lyude@redhat.com>
> > Cc: Karol Herbst <karolherbst@gmail.com>
> > Cc: Ilia Mirkin <imirkin@alum.mit.edu>
> > Cc: dri-devel@lists.freedesktop.org
> > Cc: intel-gfx@lists.freedesktop.org
> > Cc: linux-renesas-soc@vger.kernel.org
> > Reported-by: kbuild test robot <lkp@intel.com>
> > Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
> > Signed-off-by: Sean Paul <seanpaul@chromium.org>
> 
> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> 
> I have no pending conflicting changes for rcar_lvds.c. Do you plan to
> merge this through drm-misc ?

Thanks for your review!

Yeah, since the bug is only in drm-misc-next, this will also go there. Speaking
of which, I just applied it :-)

Sean

> 
> > ---
> >  drivers/gpu/drm/rcar-du/rcar_lvds.c | 4 ++--
> >  1 file changed, 2 insertions(+), 2 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/rcar-du/rcar_lvds.c b/drivers/gpu/drm/rcar-du/rcar_lvds.c
> > index f2a5d4d997073..1c62578590f46 100644
> > --- a/drivers/gpu/drm/rcar-du/rcar_lvds.c
> > +++ b/drivers/gpu/drm/rcar-du/rcar_lvds.c
> > @@ -115,8 +115,8 @@ static int rcar_lvds_connector_atomic_check(struct drm_connector *connector,
> >  
> >  	/* We're not allowed to modify the resolution. */
> >  	crtc_state = drm_atomic_get_crtc_state(state, conn_state->crtc);
> > -	if (!crtc_state)
> > -		return -EINVAL;
> > +	if (IS_ERR(crtc_state))
> > +		return PTR_ERR(crtc_state);
> >  
> >  	if (crtc_state->mode.hdisplay != panel_mode->hdisplay ||
> >  	    crtc_state->mode.vdisplay != panel_mode->vdisplay)
> 
> -- 
> Regards,
> 
> Laurent Pinchart

-- 
Sean Paul, Software Engineer, Google / Chromium OS
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