From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id CAD4AC433F5 for ; Mon, 28 Mar 2022 09:35:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233145AbiC1Jgp (ORCPT ); Mon, 28 Mar 2022 05:36:45 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38238 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232922AbiC1Jgo (ORCPT ); Mon, 28 Mar 2022 05:36:44 -0400 Received: from mailgw01.mediatek.com (unknown [60.244.123.138]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1BA2ABE36; Mon, 28 Mar 2022 02:34:59 -0700 (PDT) X-UUID: f09d385295b640569cddb54d46bf6243-20220328 X-UUID: f09d385295b640569cddb54d46bf6243-20220328 Received: from mtkexhb01.mediatek.inc [(172.21.101.102)] by mailgw01.mediatek.com (envelope-from ) (Generic MTA with TLSv1.2 ECDHE-RSA-AES256-SHA384 256/256) with ESMTP id 360122826; Mon, 28 Mar 2022 17:34:53 +0800 Received: from mtkcas10.mediatek.inc (172.21.101.39) by mtkmbs07n1.mediatek.inc (172.21.101.16) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Mon, 28 Mar 2022 17:34:51 +0800 Received: from mtksdccf07 (172.21.84.99) by mtkcas10.mediatek.inc (172.21.101.73) with Microsoft SMTP Server id 15.0.1497.2 via Frontend Transport; Mon, 28 Mar 2022 17:34:51 +0800 Message-ID: <9f14d6a0aa782a8f6c3e7044fe90d74b80d17ed0.camel@mediatek.com> Subject: Re: [PATCH v1, 1/1] drm/mediatek: fixup crtc event null pointer issue From: CK Hu To: Yongqiang Niu , Chun-Kuang Hu CC: , , David Airlie , Jassi Brar , , , "Dennis YC Hsieh" , Fabien Parent , Rob Herring , , Hsin-Yi Wang , Matthias Brugger , Date: Mon, 28 Mar 2022 17:34:51 +0800 In-Reply-To: <20220314074239.28507-2-yongqiang.niu@mediatek.com> References: <20220314074239.28507-1-yongqiang.niu@mediatek.com> <20220314074239.28507-2-yongqiang.niu@mediatek.com> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.28.5-0ubuntu0.18.04.2 MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-MTK: N Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org Hi, Yongqiang: On Mon, 2022-03-14 at 15:42 +0800, Yongqiang Niu wrote: > if crtc event is null pointer, do not send vblank event This is a bug-fix, so add a Fixes tag here. > > Signed-off-by: Yongqiang Niu > --- > drivers/gpu/drm/mediatek/mtk_drm_crtc.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/drivers/gpu/drm/mediatek/mtk_drm_crtc.c > b/drivers/gpu/drm/mediatek/mtk_drm_crtc.c > index d661edf7e0fe..265fed446628 100644 > --- a/drivers/gpu/drm/mediatek/mtk_drm_crtc.c > +++ b/drivers/gpu/drm/mediatek/mtk_drm_crtc.c > @@ -92,6 +92,9 @@ static void mtk_drm_crtc_finish_page_flip(struct > mtk_drm_crtc *mtk_crtc) > struct drm_crtc *crtc = &mtk_crtc->base; > unsigned long flags; > > + if (!mtk_crtc->event) > + return; > + > spin_lock_irqsave(&crtc->dev->event_lock, flags); > drm_crtc_send_vblank_event(crtc, mtk_crtc->event); I think pending_needs_vblank is used to protect this situation. It seems that pending_needs_vblank should be protected by critical section. Regards, CK > drm_crtc_vblank_put(crtc);