From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752339AbdHIXFr (ORCPT ); Wed, 9 Aug 2017 19:05:47 -0400 Received: from mail-pg0-f46.google.com ([74.125.83.46]:38127 "EHLO mail-pg0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752168AbdHIXFp (ORCPT ); Wed, 9 Aug 2017 19:05:45 -0400 Date: Wed, 9 Aug 2017 16:05:43 -0700 From: Matthias Kaehlcke To: zijun_hu , Andrew Morton Cc: linux-kernel@vger.kernel.org, Doug Anderson , Nick Desaulniers , Greg Hackmann , Yury Norov , Ard Biesheuvel Subject: Re: [PATCH v2] drm/rockchip: Skip suspend/resume if no display is attached Message-ID: <20170809230543.GA109008@google.com> References: <20170809230302.107975-1-mka@chromium.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20170809230302.107975-1-mka@chromium.org> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org El Wed, Aug 09, 2017 at 04:03:02PM -0700 Matthias Kaehlcke ha dit: > rockchip_drm_sys_suspend/resume() obains a struct drm_device pointer > from drvdata, the pointer is then dereferenced to obtain private data. > drvdata is set when a display is bound, on systems without a > (successfully probed) display drvdata is NULL and the PM functions > try to dereference a NULL pointer. > > The suspend/resume code relies on a valid drm_device object, skip it if > the pointer is NULL. sorry for the noise, the recipient list was taken from the command history in another tab, instead the one I intended :( > --- > drivers/gpu/drm/rockchip/rockchip_drm_drv.c | 14 ++++++++++++-- > 1 file changed, 12 insertions(+), 2 deletions(-) > > diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_drv.c b/drivers/gpu/drm/rockchip/rockchip_drm_drv.c > index c6b1b7f3a2a3..6228145d9496 100644 > --- a/drivers/gpu/drm/rockchip/rockchip_drm_drv.c > +++ b/drivers/gpu/drm/rockchip/rockchip_drm_drv.c > @@ -275,11 +275,16 @@ static void rockchip_drm_fb_resume(struct drm_device *drm) > static int rockchip_drm_sys_suspend(struct device *dev) > { > struct drm_device *drm = dev_get_drvdata(dev); > - struct rockchip_drm_private *priv = drm->dev_private; > + struct rockchip_drm_private *priv; > + > + if (!drm) > + /* no display attached */ > + return 0; > > drm_kms_helper_poll_disable(drm); > rockchip_drm_fb_suspend(drm); > > + priv = drm->dev_private; > priv->state = drm_atomic_helper_suspend(drm); > if (IS_ERR(priv->state)) { > rockchip_drm_fb_resume(drm); > @@ -293,8 +298,13 @@ static int rockchip_drm_sys_suspend(struct device *dev) > static int rockchip_drm_sys_resume(struct device *dev) > { > struct drm_device *drm = dev_get_drvdata(dev); > - struct rockchip_drm_private *priv = drm->dev_private; > + struct rockchip_drm_private *priv; > + > + if (!drm) > + /* no display attached */ > + return 0; > > + priv = drm->dev_private; > drm_atomic_helper_resume(drm, priv->state); > rockchip_drm_fb_resume(drm); > drm_kms_helper_poll_enable(drm);