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 X-Spam-Level: X-Spam-Status: No, score=-14.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 76A5AC433C1 for ; Wed, 24 Mar 2021 03:16:00 +0000 (UTC) Received: from desiato.infradead.org (desiato.infradead.org [90.155.92.199]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 070E6619C9 for ; Wed, 24 Mar 2021 03:15:59 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 070E6619C9 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=ideasonboard.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=desiato.20200630; h=Sender:Content-Transfer-Encoding :Content-Type:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References:Message-ID: Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=0xAerrsmiErWbROi1/0/oAaPNVwk0YRvKE/QrrDLpWo=; b=SfbhACXsqxDxJkMvPW6ABioyg gGX/0h+k1tQWc4yLrthT6N+ToqU/HXzL3en75Xwlg6QOIrSayX9SXWRm1F+htMtSQUzA+xkwiAxJx mkFlC56jZL82H6Rwy5PCbuyTAB3AJ+ZiRMQ/XT+XBRniiskXPdH62kby7os6B23U3FRZbG58sCJ/Q BG55dZMvnm+egrSsknvJcD/9YIXmRLY/3NaNdqNkfoxcDh9pMxpbG827x699RE8UUiOKwR/szQAWE xiisaGF3mDRO7coVKpPZKur8KPkVuIHhPIWTvJ15t7TzZS1EjGOHtwgLeuByYC/e72npaodTSLzVH lnuLA+5CQ==; Received: from localhost ([::1] helo=desiato.infradead.org) by desiato.infradead.org with esmtp (Exim 4.94 #2 (Red Hat Linux)) id 1lOtyY-00GDl1-G5; Wed, 24 Mar 2021 03:14:31 +0000 Received: from perceval.ideasonboard.com ([213.167.242.64]) by desiato.infradead.org with esmtps (Exim 4.94 #2 (Red Hat Linux)) id 1lOtyT-00GDka-EK for linux-arm-kernel@lists.infradead.org; Wed, 24 Mar 2021 03:14:27 +0000 Received: from pendragon.ideasonboard.com (62-78-145-57.bb.dnainternet.fi [62.78.145.57]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id D6B51580; Wed, 24 Mar 2021 04:14:23 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1616555664; bh=sBJb6TLMoCXie6Cz1KwQP/tND9xgZh/+QqXpqwmXWOg=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=max4LQ1tsmmi+q0VA47yv0xGMVojlAwja6LVEHrlOSEmndQVeB7aIQ3pgKGvWXVVT e4DUPuelaSftaEpkAzG+hJuL+9eemD/ws871eXW3nAl+g8OwmQOFemrQX8KC5TU4rL Ds6vFytwO1AjhwNsxWlXH7/fPwbf/P301Ji+T94o= Date: Wed, 24 Mar 2021 05:13:41 +0200 From: Laurent Pinchart To: quanyang.wang@windriver.com Cc: Hyun Kwon , David Airlie , Daniel Vetter , Michal Simek , dri-devel@lists.freedesktop.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [V2][PATCH] drm: xlnx: zynqmp: release reset to DP controller before accessing DP registers Message-ID: References: <20210323025501.1568039-1-quanyang.wang@windriver.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20210323025501.1568039-1-quanyang.wang@windriver.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210324_031425_675068_0304F4DF X-CRM114-Status: GOOD ( 26.23 ) 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: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Hi Quanyang, Thank you for the patch. On Tue, Mar 23, 2021 at 10:55:01AM +0800, quanyang.wang@windriver.com wrote: > From: Quanyang Wang > > When insmod zynqmp-dpsub.ko after rmmod it, system will hang with the > error log as below: > > root@xilinx-zynqmp:~# insmod zynqmp-dpsub.ko > [ 88.391289] [drm] Initialized zynqmp-dpsub 1.0.0 20130509 for fd4a0000.display on minor 0 > [ 88.529906] Console: switching to colour frame buffer device 128x48 > [ 88.549402] zynqmp-dpsub fd4a0000.display: [drm] fb0: zynqmp-dpsubdrm frame buffer device > [ 88.571624] zynqmp-dpsub fd4a0000.display: ZynqMP DisplayPort Subsystem driver probed > root@xilinx-zynqmp:~# rmmod zynqmp_dpsub > [ 94.023404] Console: switching to colour dummy device 80x25 > root@xilinx-zynqmp:~# insmod zynqmp-dpsub.ko > > > This is because that in zynqmp_dp_probe it tries to access some DP > registers while the DP controller is still in the reset state. When > running "rmmod zynqmp_dpsub", zynqmp_dp_reset(dp, true) in > zynqmp_dp_phy_exit is called to force the DP controller into the reset > state. Then insmod will call zynqmp_dp_probe to program the DP registers, > but at this moment the DP controller hasn't been brought out of the reset > state yet since the function zynqmp_dp_reset(dp, false) is called later and > this will result the system hang. > > Releasing the reset to DP controller before any read/write operation to it > will fix this issue. And for symmetry, move zynqmp_dp_reset() call from > zynqmp_dp_phy_exit() to zynqmp_dp_remove(). > > Signed-off-by: Quanyang Wang Reviewed-by: Laurent Pinchart > --- > > V2: > According to Laurent's comments: > - add zynqmp_dp_reset(dp, true) in error path in zynqmp_dp_probe > - move the zynqmp_dp_reset() call from zynqmp_dp_phy_exit() to zynqmp_dp_remove() > > --- > drivers/gpu/drm/xlnx/zynqmp_dp.c | 22 ++++++++++++---------- > 1 file changed, 12 insertions(+), 10 deletions(-) > > diff --git a/drivers/gpu/drm/xlnx/zynqmp_dp.c b/drivers/gpu/drm/xlnx/zynqmp_dp.c > index 99158ee67d02..337adf0769ad 100644 > --- a/drivers/gpu/drm/xlnx/zynqmp_dp.c > +++ b/drivers/gpu/drm/xlnx/zynqmp_dp.c > @@ -402,10 +402,6 @@ static int zynqmp_dp_phy_init(struct zynqmp_dp *dp) > } > } > > - ret = zynqmp_dp_reset(dp, false); > - if (ret < 0) > - return ret; > - > zynqmp_dp_clr(dp, ZYNQMP_DP_PHY_RESET, ZYNQMP_DP_PHY_RESET_ALL_RESET); > > /* > @@ -441,8 +437,6 @@ static void zynqmp_dp_phy_exit(struct zynqmp_dp *dp) > ret); > } > > - zynqmp_dp_reset(dp, true); > - > for (i = 0; i < dp->num_lanes; i++) { > ret = phy_exit(dp->phy[i]); > if (ret) > @@ -1682,9 +1676,13 @@ int zynqmp_dp_probe(struct zynqmp_dpsub *dpsub, struct drm_device *drm) > return PTR_ERR(dp->reset); > } > > + ret = zynqmp_dp_reset(dp, false); > + if (ret < 0) > + return ret; > + > ret = zynqmp_dp_phy_probe(dp); > if (ret) > - return ret; > + goto err_reset; > > /* Initialize the hardware. */ > zynqmp_dp_write(dp, ZYNQMP_DP_TX_PHY_POWER_DOWN, > @@ -1696,7 +1694,7 @@ int zynqmp_dp_probe(struct zynqmp_dpsub *dpsub, struct drm_device *drm) > > ret = zynqmp_dp_phy_init(dp); > if (ret) > - return ret; > + goto err_reset; > > zynqmp_dp_write(dp, ZYNQMP_DP_TRANSMITTER_ENABLE, 1); > > @@ -1708,15 +1706,18 @@ int zynqmp_dp_probe(struct zynqmp_dpsub *dpsub, struct drm_device *drm) > zynqmp_dp_irq_handler, IRQF_ONESHOT, > dev_name(dp->dev), dp); > if (ret < 0) > - goto error; > + goto err_phy_exit; > > dev_dbg(dp->dev, "ZynqMP DisplayPort Tx probed with %u lanes\n", > dp->num_lanes); > > return 0; > > -error: > +err_phy_exit: > zynqmp_dp_phy_exit(dp); > +err_reset: > + zynqmp_dp_reset(dp, true); > + > return ret; > } > > @@ -1734,4 +1735,5 @@ void zynqmp_dp_remove(struct zynqmp_dpsub *dpsub) > zynqmp_dp_write(dp, ZYNQMP_DP_INT_DS, 0xffffffff); > > zynqmp_dp_phy_exit(dp); > + zynqmp_dp_reset(dp, true); > } -- Regards, Laurent Pinchart _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel 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 X-Spam-Level: X-Spam-Status: No, score=-13.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E24A2C433C1 for ; Wed, 24 Mar 2021 03:14:26 +0000 (UTC) Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 9A496619C9 for ; Wed, 24 Mar 2021 03:14:26 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 9A496619C9 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=ideasonboard.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=dri-devel-bounces@lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 07C806E2DF; Wed, 24 Mar 2021 03:14:26 +0000 (UTC) Received: from perceval.ideasonboard.com (perceval.ideasonboard.com [213.167.242.64]) by gabe.freedesktop.org (Postfix) with ESMTPS id 76B5D6E2DF for ; Wed, 24 Mar 2021 03:14:25 +0000 (UTC) Received: from pendragon.ideasonboard.com (62-78-145-57.bb.dnainternet.fi [62.78.145.57]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id D6B51580; Wed, 24 Mar 2021 04:14:23 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1616555664; bh=sBJb6TLMoCXie6Cz1KwQP/tND9xgZh/+QqXpqwmXWOg=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=max4LQ1tsmmi+q0VA47yv0xGMVojlAwja6LVEHrlOSEmndQVeB7aIQ3pgKGvWXVVT e4DUPuelaSftaEpkAzG+hJuL+9eemD/ws871eXW3nAl+g8OwmQOFemrQX8KC5TU4rL Ds6vFytwO1AjhwNsxWlXH7/fPwbf/P301Ji+T94o= Date: Wed, 24 Mar 2021 05:13:41 +0200 From: Laurent Pinchart To: quanyang.wang@windriver.com Subject: Re: [V2][PATCH] drm: xlnx: zynqmp: release reset to DP controller before accessing DP registers Message-ID: References: <20210323025501.1568039-1-quanyang.wang@windriver.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20210323025501.1568039-1-quanyang.wang@windriver.com> X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Hyun Kwon , David Airlie , Michal Simek , dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" Hi Quanyang, Thank you for the patch. On Tue, Mar 23, 2021 at 10:55:01AM +0800, quanyang.wang@windriver.com wrote: > From: Quanyang Wang > > When insmod zynqmp-dpsub.ko after rmmod it, system will hang with the > error log as below: > > root@xilinx-zynqmp:~# insmod zynqmp-dpsub.ko > [ 88.391289] [drm] Initialized zynqmp-dpsub 1.0.0 20130509 for fd4a0000.display on minor 0 > [ 88.529906] Console: switching to colour frame buffer device 128x48 > [ 88.549402] zynqmp-dpsub fd4a0000.display: [drm] fb0: zynqmp-dpsubdrm frame buffer device > [ 88.571624] zynqmp-dpsub fd4a0000.display: ZynqMP DisplayPort Subsystem driver probed > root@xilinx-zynqmp:~# rmmod zynqmp_dpsub > [ 94.023404] Console: switching to colour dummy device 80x25 > root@xilinx-zynqmp:~# insmod zynqmp-dpsub.ko > > > This is because that in zynqmp_dp_probe it tries to access some DP > registers while the DP controller is still in the reset state. When > running "rmmod zynqmp_dpsub", zynqmp_dp_reset(dp, true) in > zynqmp_dp_phy_exit is called to force the DP controller into the reset > state. Then insmod will call zynqmp_dp_probe to program the DP registers, > but at this moment the DP controller hasn't been brought out of the reset > state yet since the function zynqmp_dp_reset(dp, false) is called later and > this will result the system hang. > > Releasing the reset to DP controller before any read/write operation to it > will fix this issue. And for symmetry, move zynqmp_dp_reset() call from > zynqmp_dp_phy_exit() to zynqmp_dp_remove(). > > Signed-off-by: Quanyang Wang Reviewed-by: Laurent Pinchart > --- > > V2: > According to Laurent's comments: > - add zynqmp_dp_reset(dp, true) in error path in zynqmp_dp_probe > - move the zynqmp_dp_reset() call from zynqmp_dp_phy_exit() to zynqmp_dp_remove() > > --- > drivers/gpu/drm/xlnx/zynqmp_dp.c | 22 ++++++++++++---------- > 1 file changed, 12 insertions(+), 10 deletions(-) > > diff --git a/drivers/gpu/drm/xlnx/zynqmp_dp.c b/drivers/gpu/drm/xlnx/zynqmp_dp.c > index 99158ee67d02..337adf0769ad 100644 > --- a/drivers/gpu/drm/xlnx/zynqmp_dp.c > +++ b/drivers/gpu/drm/xlnx/zynqmp_dp.c > @@ -402,10 +402,6 @@ static int zynqmp_dp_phy_init(struct zynqmp_dp *dp) > } > } > > - ret = zynqmp_dp_reset(dp, false); > - if (ret < 0) > - return ret; > - > zynqmp_dp_clr(dp, ZYNQMP_DP_PHY_RESET, ZYNQMP_DP_PHY_RESET_ALL_RESET); > > /* > @@ -441,8 +437,6 @@ static void zynqmp_dp_phy_exit(struct zynqmp_dp *dp) > ret); > } > > - zynqmp_dp_reset(dp, true); > - > for (i = 0; i < dp->num_lanes; i++) { > ret = phy_exit(dp->phy[i]); > if (ret) > @@ -1682,9 +1676,13 @@ int zynqmp_dp_probe(struct zynqmp_dpsub *dpsub, struct drm_device *drm) > return PTR_ERR(dp->reset); > } > > + ret = zynqmp_dp_reset(dp, false); > + if (ret < 0) > + return ret; > + > ret = zynqmp_dp_phy_probe(dp); > if (ret) > - return ret; > + goto err_reset; > > /* Initialize the hardware. */ > zynqmp_dp_write(dp, ZYNQMP_DP_TX_PHY_POWER_DOWN, > @@ -1696,7 +1694,7 @@ int zynqmp_dp_probe(struct zynqmp_dpsub *dpsub, struct drm_device *drm) > > ret = zynqmp_dp_phy_init(dp); > if (ret) > - return ret; > + goto err_reset; > > zynqmp_dp_write(dp, ZYNQMP_DP_TRANSMITTER_ENABLE, 1); > > @@ -1708,15 +1706,18 @@ int zynqmp_dp_probe(struct zynqmp_dpsub *dpsub, struct drm_device *drm) > zynqmp_dp_irq_handler, IRQF_ONESHOT, > dev_name(dp->dev), dp); > if (ret < 0) > - goto error; > + goto err_phy_exit; > > dev_dbg(dp->dev, "ZynqMP DisplayPort Tx probed with %u lanes\n", > dp->num_lanes); > > return 0; > > -error: > +err_phy_exit: > zynqmp_dp_phy_exit(dp); > +err_reset: > + zynqmp_dp_reset(dp, true); > + > return ret; > } > > @@ -1734,4 +1735,5 @@ void zynqmp_dp_remove(struct zynqmp_dpsub *dpsub) > zynqmp_dp_write(dp, ZYNQMP_DP_INT_DS, 0xffffffff); > > zynqmp_dp_phy_exit(dp); > + zynqmp_dp_reset(dp, true); > } -- Regards, Laurent Pinchart _______________________________________________ dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel 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 X-Spam-Level: X-Spam-Status: No, score=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id D104FC433DB for ; Wed, 24 Mar 2021 03:15:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9D154619C9 for ; Wed, 24 Mar 2021 03:15:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232528AbhCXDOn (ORCPT ); Tue, 23 Mar 2021 23:14:43 -0400 Received: from perceval.ideasonboard.com ([213.167.242.64]:51052 "EHLO perceval.ideasonboard.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232445AbhCXDOZ (ORCPT ); Tue, 23 Mar 2021 23:14:25 -0400 Received: from pendragon.ideasonboard.com (62-78-145-57.bb.dnainternet.fi [62.78.145.57]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id D6B51580; Wed, 24 Mar 2021 04:14:23 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1616555664; bh=sBJb6TLMoCXie6Cz1KwQP/tND9xgZh/+QqXpqwmXWOg=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=max4LQ1tsmmi+q0VA47yv0xGMVojlAwja6LVEHrlOSEmndQVeB7aIQ3pgKGvWXVVT e4DUPuelaSftaEpkAzG+hJuL+9eemD/ws871eXW3nAl+g8OwmQOFemrQX8KC5TU4rL Ds6vFytwO1AjhwNsxWlXH7/fPwbf/P301Ji+T94o= Date: Wed, 24 Mar 2021 05:13:41 +0200 From: Laurent Pinchart To: quanyang.wang@windriver.com Cc: Hyun Kwon , David Airlie , Daniel Vetter , Michal Simek , dri-devel@lists.freedesktop.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [V2][PATCH] drm: xlnx: zynqmp: release reset to DP controller before accessing DP registers Message-ID: References: <20210323025501.1568039-1-quanyang.wang@windriver.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20210323025501.1568039-1-quanyang.wang@windriver.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Quanyang, Thank you for the patch. On Tue, Mar 23, 2021 at 10:55:01AM +0800, quanyang.wang@windriver.com wrote: > From: Quanyang Wang > > When insmod zynqmp-dpsub.ko after rmmod it, system will hang with the > error log as below: > > root@xilinx-zynqmp:~# insmod zynqmp-dpsub.ko > [ 88.391289] [drm] Initialized zynqmp-dpsub 1.0.0 20130509 for fd4a0000.display on minor 0 > [ 88.529906] Console: switching to colour frame buffer device 128x48 > [ 88.549402] zynqmp-dpsub fd4a0000.display: [drm] fb0: zynqmp-dpsubdrm frame buffer device > [ 88.571624] zynqmp-dpsub fd4a0000.display: ZynqMP DisplayPort Subsystem driver probed > root@xilinx-zynqmp:~# rmmod zynqmp_dpsub > [ 94.023404] Console: switching to colour dummy device 80x25 > root@xilinx-zynqmp:~# insmod zynqmp-dpsub.ko > > > This is because that in zynqmp_dp_probe it tries to access some DP > registers while the DP controller is still in the reset state. When > running "rmmod zynqmp_dpsub", zynqmp_dp_reset(dp, true) in > zynqmp_dp_phy_exit is called to force the DP controller into the reset > state. Then insmod will call zynqmp_dp_probe to program the DP registers, > but at this moment the DP controller hasn't been brought out of the reset > state yet since the function zynqmp_dp_reset(dp, false) is called later and > this will result the system hang. > > Releasing the reset to DP controller before any read/write operation to it > will fix this issue. And for symmetry, move zynqmp_dp_reset() call from > zynqmp_dp_phy_exit() to zynqmp_dp_remove(). > > Signed-off-by: Quanyang Wang Reviewed-by: Laurent Pinchart > --- > > V2: > According to Laurent's comments: > - add zynqmp_dp_reset(dp, true) in error path in zynqmp_dp_probe > - move the zynqmp_dp_reset() call from zynqmp_dp_phy_exit() to zynqmp_dp_remove() > > --- > drivers/gpu/drm/xlnx/zynqmp_dp.c | 22 ++++++++++++---------- > 1 file changed, 12 insertions(+), 10 deletions(-) > > diff --git a/drivers/gpu/drm/xlnx/zynqmp_dp.c b/drivers/gpu/drm/xlnx/zynqmp_dp.c > index 99158ee67d02..337adf0769ad 100644 > --- a/drivers/gpu/drm/xlnx/zynqmp_dp.c > +++ b/drivers/gpu/drm/xlnx/zynqmp_dp.c > @@ -402,10 +402,6 @@ static int zynqmp_dp_phy_init(struct zynqmp_dp *dp) > } > } > > - ret = zynqmp_dp_reset(dp, false); > - if (ret < 0) > - return ret; > - > zynqmp_dp_clr(dp, ZYNQMP_DP_PHY_RESET, ZYNQMP_DP_PHY_RESET_ALL_RESET); > > /* > @@ -441,8 +437,6 @@ static void zynqmp_dp_phy_exit(struct zynqmp_dp *dp) > ret); > } > > - zynqmp_dp_reset(dp, true); > - > for (i = 0; i < dp->num_lanes; i++) { > ret = phy_exit(dp->phy[i]); > if (ret) > @@ -1682,9 +1676,13 @@ int zynqmp_dp_probe(struct zynqmp_dpsub *dpsub, struct drm_device *drm) > return PTR_ERR(dp->reset); > } > > + ret = zynqmp_dp_reset(dp, false); > + if (ret < 0) > + return ret; > + > ret = zynqmp_dp_phy_probe(dp); > if (ret) > - return ret; > + goto err_reset; > > /* Initialize the hardware. */ > zynqmp_dp_write(dp, ZYNQMP_DP_TX_PHY_POWER_DOWN, > @@ -1696,7 +1694,7 @@ int zynqmp_dp_probe(struct zynqmp_dpsub *dpsub, struct drm_device *drm) > > ret = zynqmp_dp_phy_init(dp); > if (ret) > - return ret; > + goto err_reset; > > zynqmp_dp_write(dp, ZYNQMP_DP_TRANSMITTER_ENABLE, 1); > > @@ -1708,15 +1706,18 @@ int zynqmp_dp_probe(struct zynqmp_dpsub *dpsub, struct drm_device *drm) > zynqmp_dp_irq_handler, IRQF_ONESHOT, > dev_name(dp->dev), dp); > if (ret < 0) > - goto error; > + goto err_phy_exit; > > dev_dbg(dp->dev, "ZynqMP DisplayPort Tx probed with %u lanes\n", > dp->num_lanes); > > return 0; > > -error: > +err_phy_exit: > zynqmp_dp_phy_exit(dp); > +err_reset: > + zynqmp_dp_reset(dp, true); > + > return ret; > } > > @@ -1734,4 +1735,5 @@ void zynqmp_dp_remove(struct zynqmp_dpsub *dpsub) > zynqmp_dp_write(dp, ZYNQMP_DP_INT_DS, 0xffffffff); > > zynqmp_dp_phy_exit(dp); > + zynqmp_dp_reset(dp, true); > } -- Regards, Laurent Pinchart