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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 416DCCD3430 for ; Mon, 4 May 2026 15:24:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=xYNcXti+b8H0n24uR4D8nmzORNoE6W+mXIeBUy7ZNjg=; b=dLw7I1ijdmQkXJ1Be1s8aZXrxP kFZe1JQmee1iTvOGq9osmWYUohbTXHMN9jHTllvgBnM5gt5XIf3xTHX2mXq1MYUR3EeodoOS64QrW 4F5CtgM7/yzsQ3bJTj7b3O+GM87IjR5LQiaJFHxSbhsAsgkCB5ztsDd/yddrEzhrOA3zMh3bRciZ3 dBfR/IAJcOREemt1wS9UdyEjjE1oEmRuue7H5YgPzniGt64vinY+elDMHVPGHodpijDKnW8MNyk6E bPJ67OR18VtvX56SU53UpUAfZcYE7wAxOn1Efi6dQaNHhMNerfoUhCWXrt6P1tn1hTWMDrytn4Erw jzhZNYWg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1wJv9j-0000000DazG-1iJx; Mon, 04 May 2026 15:24:23 +0000 Received: from perceval.ideasonboard.com ([213.167.242.64]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1wJv9h-0000000Dayg-1JzS for linux-arm-kernel@lists.infradead.org; Mon, 04 May 2026 15:24:22 +0000 Received: from killaraus.ideasonboard.com (2001-14ba-703d-e500--2a1.rev.dnainternet.fi [IPv6:2001:14ba:703d:e500::2a1]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id 7D9E7175; Mon, 4 May 2026 17:24:17 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1777908257; bh=yz5CJzoCekoxmuhkSUxICdRVDMPN012+4TnwLeJXyT0=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=B61SUdKbg+TBoeJcmGjMgIBh7kyNGLwCDoIVmQHw6UmyS2Z3VRmOTu/32ZobUYVGW dbG6Benp8XPSbsjfBi1yDix1qMnHaedC+BVRBFN+KPYfu6fGF3RspbWz7B7ImZAjVX NZ+NnuYkhZh2W4rpi11v3DQfaPbKXmN+hkOONYx8= Date: Mon, 4 May 2026 18:24:18 +0300 From: Laurent Pinchart To: Luca Ceresoli Cc: Andrzej Hajda , Neil Armstrong , Robert Foss , Jonas Karlman , Jernej Skrabec , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Simona Vetter , Rob Clark , Dmitry Baryshkov , Abhinav Kumar , Jessica Zhang , Sean Paul , Marijn Suijten , Sumit Semwal , John Stultz , Tomi Valkeinen , Michal Simek , Hui Pu , Ian Ray , Thomas Petazzoni , dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org, freedreno@lists.freedesktop.org, linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH v4 10/11] drm: zynqmp_dp: switch to of_drm_get_bridge_by_endpoint() Message-ID: <20260504152418.GC1455860@killaraus.ideasonboard.com> References: <20260504-drm-bridge-alloc-getput-panel_or_bridge-v4-0-b578c3daaf10@bootlin.com> <20260504-drm-bridge-alloc-getput-panel_or_bridge-v4-10-b578c3daaf10@bootlin.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20260504-drm-bridge-alloc-getput-panel_or_bridge-v4-10-b578c3daaf10@bootlin.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260504_082421_581633_193FFA0A X-CRM114-Status: GOOD ( 25.73 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Hi Luca, Thank you for the patch. On Mon, May 04, 2026 at 12:45:13PM +0200, Luca Ceresoli wrote: > This driver calls drm_of_find_panel_or_bridge() with a NULL pointer in the > @panel parameter, thus using a reduced feature set of that function. > Replace this call with the simpler of_drm_get_bridge_by_endpoint(). > > Since of_drm_get_bridge_by_endpoint() increases the refcount of the > returned bridge, ensure it is put on removal. To achieve this, instead of > adding an explicit drm_bridge_put(), migrate to the bridge::next_bridge > pointer which is automatically put when the bridge is eventually freed. > > Signed-off-by: Luca Ceresoli > --- > > Changes in v4: > - fix missing assignment > > Changes in v3: > - fix ERR_PTR deref when -ENODEV is returned > --- > drivers/gpu/drm/xlnx/zynqmp_dp.c | 19 +++++++++++-------- > 1 file changed, 11 insertions(+), 8 deletions(-) > > diff --git a/drivers/gpu/drm/xlnx/zynqmp_dp.c b/drivers/gpu/drm/xlnx/zynqmp_dp.c > index 379180fb3004..fd30491a6697 100644 > --- a/drivers/gpu/drm/xlnx/zynqmp_dp.c > +++ b/drivers/gpu/drm/xlnx/zynqmp_dp.c > @@ -353,7 +353,6 @@ struct zynqmp_dp_train_set_priv { > * @lock: Mutex protecting this struct and register access (but not AUX) > * @irq: irq > * @bridge: DRM bridge for the DP encoder > - * @next_bridge: The downstream bridge > * @test: Configuration for test mode > * @config: IP core configuration from DTS > * @aux: aux channel > @@ -385,7 +384,6 @@ struct zynqmp_dp { > struct completion aux_done; > struct mutex lock; > > - struct drm_bridge *next_bridge; > struct device *dev; > struct zynqmp_dpsub *dpsub; > void __iomem *iomem; > @@ -1494,8 +1492,8 @@ static int zynqmp_dp_bridge_attach(struct drm_bridge *bridge, > return ret; > } > > - if (dp->next_bridge) { > - ret = drm_bridge_attach(encoder, dp->next_bridge, > + if (dp->bridge.next_bridge) { > + ret = drm_bridge_attach(encoder, dp->bridge.next_bridge, > bridge, flags); > if (ret < 0) > goto error; > @@ -2461,10 +2459,15 @@ int zynqmp_dp_probe(struct zynqmp_dpsub *dpsub) > * Acquire the next bridge in the chain. Ignore errors caused by port@5 > * not being connected for backward-compatibility with older DTs. > */ > - ret = drm_of_find_panel_or_bridge(dp->dev->of_node, 5, 0, NULL, > - &dp->next_bridge); > - if (ret < 0 && ret != -ENODEV) > - goto err_reset; > + dp->bridge.next_bridge = of_drm_get_bridge_by_endpoint(dp->dev->of_node, 5, 0); > + if (IS_ERR(dp->bridge.next_bridge)) { > + if (PTR_ERR(dp->bridge.next_bridge) == -ENODEV) { > + dp->bridge.next_bridge = NULL; > + } else { > + ret = PTR_ERR(dp->bridge.next_bridge); > + goto err_reset; > + } I would find if (PTR_ERR(dp->bridge.next_bridge) != -ENODEV) { ret = PTR_ERR(dp->bridge.next_bridge); goto err_reset; } dp->bridge.next_bridge = NULL; easier to read. Up to you. Reviewed-by: Laurent Pinchart > + } > > /* Initialize the hardware. */ > dp->config.misc0 &= ~ZYNQMP_DP_MAIN_STREAM_MISC0_SYNC_LOCK; -- Regards, Laurent Pinchart