From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from perceval.ideasonboard.com (perceval.ideasonboard.com [213.167.242.64]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 9CB71142649 for ; Mon, 6 May 2024 11:16:26 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=213.167.242.64 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1714994188; cv=none; b=rmSMsLjpIudMG8lwoXuraZgqapKN51Mvo1C4tw3VE1xoPa0cdoQyDEPGT6gi6h4pFdjgdikhY6gCT+WLYydGDdxP8yBh7GWuGjz40KrjcENWA363x08UiHtTgiqaK9FwvoiuxDmW8l7I4awtFZqc0yA3SuJd2XLJFwe0IjjGHa4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1714994188; c=relaxed/simple; bh=5Yf4q20EuBHbQYLGxfSZZAolJNYfiPCEO3OlE+r8l1Q=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=C0NovymzpCgewWvsn1S1XA3jazHLmMm9sJnhScTFPSuyrG3YzxAdB46K/gyzyyNS6s7MlZh7P/d9d4o6lUL+B24OZKnCjTQsWFXxe5WTE0egcuM6b4HHtPQLNlUI+A+wfOR/FypCOb3giPN9lcd/qDDe5El8Vl1/qQ6ABK/rcFk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=ideasonboard.com; spf=pass smtp.mailfrom=ideasonboard.com; dkim=pass (1024-bit key) header.d=ideasonboard.com header.i=@ideasonboard.com header.b=ugF9A9mk; arc=none smtp.client-ip=213.167.242.64 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=ideasonboard.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=ideasonboard.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=ideasonboard.com header.i=@ideasonboard.com header.b="ugF9A9mk" Received: from [192.168.88.20] (91-152-88-126.elisa-laajakaista.fi [91.152.88.126]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id B134D899; Mon, 6 May 2024 13:16:22 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1714994183; bh=5Yf4q20EuBHbQYLGxfSZZAolJNYfiPCEO3OlE+r8l1Q=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=ugF9A9mkOXeI4Ogv2afJcLxHbTlTqvhLVhMjS8WrtbWjrSI+8FFZ/snCNTL3yj9Hx m2vjbba+BVvk9/aCd36naKOqhsY0n2ZSdcd2J83mGvB5jwz7jseF0lCvpyc4X0/3e2 X8ivtnW6pYKntEmUYZWLMBUWaBdkYH+rkCA4rVPY= Message-ID: <363e6d48-3e40-4578-b6f6-17323395b49b@ideasonboard.com> Date: Mon, 6 May 2024 14:16:21 +0300 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [BUG] drm: zynqmp_dp: Lockup in zynqmp_dp_bridge_detect when device is unbound To: Sean Anderson , Laurent Pinchart Cc: Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Daniel Vetter , Michal Simek , dri-devel@lists.freedesktop.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org References: <4d8f4c9b-2efb-4774-9a37-2f257f79b2c9@linux.dev> From: Tomi Valkeinen Content-Language: en-US Autocrypt: addr=tomi.valkeinen@ideasonboard.com; keydata= xsFNBE6ms0cBEACyizowecZqXfMZtnBniOieTuFdErHAUyxVgtmr0f5ZfIi9Z4l+uUN4Zdw2 wCEZjx3o0Z34diXBaMRJ3rAk9yB90UJAnLtb8A97Oq64DskLF81GCYB2P1i0qrG7UjpASgCA Ru0lVvxsWyIwSfoYoLrazbT1wkWRs8YBkkXQFfL7Mn3ZMoGPcpfwYH9O7bV1NslbmyJzRCMO eYV258gjCcwYlrkyIratlHCek4GrwV8Z9NQcjD5iLzrONjfafrWPwj6yn2RlL0mQEwt1lOvn LnI7QRtB3zxA3yB+FLsT1hx0va6xCHpX3QO2gBsyHCyVafFMrg3c/7IIWkDLngJxFgz6DLiA G4ld1QK/jsYqfP2GIMH1mFdjY+iagG4DqOsjip479HCWAptpNxSOCL6z3qxCU8MCz8iNOtZk DYXQWVscM5qgYSn+fmMM2qN+eoWlnCGVURZZLDjg387S2E1jT/dNTOsM/IqQj+ZROUZuRcF7 0RTtuU5q1HnbRNwy+23xeoSGuwmLQ2UsUk7Q5CnrjYfiPo3wHze8avK95JBoSd+WIRmV3uoO rXCoYOIRlDhg9XJTrbnQ3Ot5zOa0Y9c4IpyAlut6mDtxtKXr4+8OzjSVFww7tIwadTK3wDQv Bus4jxHjS6dz1g2ypT65qnHen6mUUH63lhzewqO9peAHJ0SLrQARAQABzTBUb21pIFZhbGtl aW5lbiA8dG9taS52YWxrZWluZW5AaWRlYXNvbmJvYXJkLmNvbT7CwY4EEwEIADgWIQTEOAw+ ll79gQef86f6PaqMvJYe9QUCX/HruAIbAwULCQgHAgYVCgkICwIEFgIDAQIeAQIXgAAKCRD6 PaqMvJYe9WmFD/99NGoD5lBJhlFDHMZvO+Op8vCwnIRZdTsyrtGl72rVh9xRfcSgYPZUvBuT VDxE53mY9HaZyu1eGMccYRBaTLJSfCXl/g317CrMNdY0k40b9YeIX10feiRYEWoDIPQ3tMmA 0nHDygzcnuPiPT68JYZ6tUOvAt7r6OX/litM+m2/E9mtp8xCoWOo/kYO4mOAIoMNvLB8vufi uBB4e/AvAjtny4ScuNV5c5q8MkfNIiOyag9QCiQ/JfoAqzXRjVb4VZG72AKaElwipiKCWEcU R4+Bu5Qbaxj7Cd36M/bI54OrbWWETJkVVSV1i0tghCd6HHyquTdFl7wYcz6cL1hn/6byVnD+ sR3BLvSBHYp8WSwv0TCuf6tLiNgHAO1hWiQ1pOoXyMEsxZlgPXT+wb4dbNVunckwqFjGxRbl Rz7apFT/ZRwbazEzEzNyrBOfB55xdipG/2+SmFn0oMFqFOBEszXLQVslh64lI0CMJm2OYYe3 PxHqYaztyeXsx13Bfnq9+bUynAQ4uW1P5DJ3OIRZWKmbQd/Me3Fq6TU57LsvwRgE0Le9PFQs dcP2071rMTpqTUteEgODJS4VDf4lXJfY91u32BJkiqM7/62Cqatcz5UWWHq5xeF03MIUTqdE qHWk3RJEoWHWQRzQfcx6Fn2fDAUKhAddvoopfcjAHfpAWJ+ENc7BTQROprNHARAAx0aat8GU hsusCLc4MIxOQwidecCTRc9Dz/7U2goUwhw2O5j9TPqLtp57VITmHILnvZf6q3QAho2QMQyE DDvHubrdtEoqaaSKxKkFie1uhWNNvXPhwkKLYieyL9m2JdU+b88HaDnpzdyTTR4uH7wk0bBa KbTSgIFDDe5lXInypewPO30TmYNkFSexnnM3n1PBCqiJXsJahE4ZQ+WnV5FbPUj8T2zXS2xk 0LZ0+DwKmZ0ZDovvdEWRWrz3UzJ8DLHb7blPpGhmqj3ANXQXC7mb9qJ6J/VSl61GbxIO2Dwb xPNkHk8fwnxlUBCOyBti/uD2uSTgKHNdabhVm2dgFNVuS1y3bBHbI/qjC3J7rWE0WiaHWEqy UVPk8rsph4rqITsj2RiY70vEW0SKePrChvET7D8P1UPqmveBNNtSS7In+DdZ5kUqLV7rJnM9 /4cwy+uZUt8cuCZlcA5u8IsBCNJudxEqBG10GHg1B6h1RZIz9Q9XfiBdaqa5+CjyFs8ua01c 9HmyfkuhXG2OLjfQuK+Ygd56mV3lq0aFdwbaX16DG22c6flkkBSjyWXYepFtHz9KsBS0DaZb 4IkLmZwEXpZcIOQjQ71fqlpiXkXSIaQ6YMEs8WjBbpP81h7QxWIfWtp+VnwNGc6nq5IQDESH mvQcsFS7d3eGVI6eyjCFdcAO8eMAEQEAAcLBXwQYAQIACQUCTqazRwIbDAAKCRD6PaqMvJYe 9fA7EACS6exUedsBKmt4pT7nqXBcRsqm6YzT6DeCM8PWMTeaVGHiR4TnNFiT3otD5UpYQI7S suYxoTdHrrrBzdlKe5rUWpzoZkVK6p0s9OIvGzLT0lrb0HC9iNDWT3JgpYDnk4Z2mFi6tTbq xKMtpVFRA6FjviGDRsfkfoURZI51nf2RSAk/A8BEDDZ7lgJHskYoklSpwyrXhkp9FHGMaYII m9EKuUTX9JPDG2FTthCBrdsgWYPdJQvM+zscq09vFMQ9Fykbx5N8z/oFEUy3ACyPqW2oyfvU CH5WDpWBG0s5BALp1gBJPytIAd/pY/5ZdNoi0Cx3+Z7jaBFEyYJdWy1hGddpkgnMjyOfLI7B CFrdecTZbR5upjNSDvQ7RG85SnpYJTIin+SAUazAeA2nS6gTZzumgtdw8XmVXZwdBfF+ICof 92UkbYcYNbzWO/GHgsNT1WnM4sa9lwCSWH8Fw1o/3bX1VVPEsnESOfxkNdu+gAF5S6+I6n3a ueeIlwJl5CpT5l8RpoZXEOVtXYn8zzOJ7oGZYINRV9Pf8qKGLf3Dft7zKBP832I3PQjeok7F yjt+9S+KgSFSHP3Pa4E7lsSdWhSlHYNdG/czhoUkSCN09C0rEK93wxACx3vtxPLjXu6RptBw 3dRq7n+mQChEB1am0BueV1JZaBboIL0AGlSJkm23kw== In-Reply-To: <4d8f4c9b-2efb-4774-9a37-2f257f79b2c9@linux.dev> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Hi, On 04/05/2024 00:54, Sean Anderson wrote: > Hi, > > I have discovered a bug in the displayport driver on drm-misc-next. To > trigger it, run > > echo fd4a0000.display > /sys/bus/platform/drivers/zynqmp-dpsub/unbind > > The system will become unresponsive and (after a bit) splat with a hard > LOCKUP. One core will be unresponsive at the first zynqmp_dp_read in > zynqmp_dp_bridge_detect. > > I believe the issue is due the registers being unmapped and the block > put into reset in zynqmp_dp_remove instead of zynqmp_dpsub_release. This > could be resolved by deferring things until zynqmp_dpsub_release > (requiring us to skip devm_*), or by adding a flag to struct zynqmp_dp > and checking it before each callback. A subsystem-level implementation > might be better for the latter. > > For a better traceback, try applying the below patch and running the > following commands before triggering the lockup: > > echo 4 > /sys/module/drm/parameters/debug > echo 8 > /proc/sys/kernel/printk I wasn't able to reproduce. Where does the detect call come in your case? Looking at the code, afaics, it shouldn't happen. Tomi > diff --git a/drivers/gpu/drm/xlnx/zynqmp_dp.c b/drivers/gpu/drm/xlnx/zynqmp_dp.c > index 9df068a413f3..17b477b14ab5 100644 > --- a/drivers/gpu/drm/xlnx/zynqmp_dp.c > +++ b/drivers/gpu/drm/xlnx/zynqmp_dp.c > @@ -296,6 +296,7 @@ struct zynqmp_dp_config { > * @train_set: set of training data > */ > struct zynqmp_dp { > + unsigned long long magic; > struct device *dev; > struct zynqmp_dpsub *dpsub; > void __iomem *iomem; > @@ -1533,6 +1534,8 @@ static enum drm_connector_status zynqmp_dp_bridge_detect(struct drm_bridge *brid > u32 state, i; > int ret; > > + WARN_ON(dp->magic != 0x0123456789abcdefULL); > + > /* > * This is from heuristic. It takes some delay (ex, 100 ~ 500 msec) to > * get the HPD signal with some monitors. > @@ -1723,6 +1726,7 @@ int zynqmp_dp_probe(struct zynqmp_dpsub *dpsub) > if (!dp) > return -ENOMEM; > > + dp->magic = 0x0123456789abcdefULL; > dp->dev = &pdev->dev; > dp->dpsub = dpsub; > dp->status = connector_status_disconnected; > @@ -1839,4 +1843,5 @@ void zynqmp_dp_remove(struct zynqmp_dpsub *dpsub) > > zynqmp_dp_phy_exit(dp); > zynqmp_dp_reset(dp, true); > + dp->magic = 0xdeadbeefdeadbeefULL; > } 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 D08FBC25B5C for ; Mon, 6 May 2024 11:16:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:Content-Type: Content-Transfer-Encoding:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:From:References:Cc:To:Subject: MIME-Version:Date:Message-ID:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=zrzxbtn6AGjtEEu0zrex5fWsGAhqqDnDsC+fkDcbLX8=; b=K/g/lrZXXNsCfn xDnDNld76J3aHR/Cnc++bL/42h63h+nDD6cHNbXLqhFcN5DUpnDc+qrgdIPsFER+a26epsMa+8VOV txA0ednyDuo9juHM8Lsx5frUiL1o2RxVEgsjHpyC/BIQ6727uq6GkMntB1f8bboMypvSM5v1237Ee mtdYEK7WKqxaX20560AzrwoI4r5qfR3kadiU2hfouFbMZ8awvFMsG5vTEbh+2efwCHwbF24DJ1REe 7wwKHKEHigWu1CL8GLXEIYeNmQmfAr5w1cW9C7A5mWaCVUJq06voHDCjEtV3ZlwTrCFG3KK+60qgX VGcRDppZ8uEE5/DpCpPA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1s3wKb-000000075CD-2IB8; Mon, 06 May 2024 11:16:29 +0000 Received: from perceval.ideasonboard.com ([213.167.242.64]) by bombadil.infradead.org with esmtps (Exim 4.97.1 #2 (Red Hat Linux)) id 1s3wKZ-000000075B0-0zhR for linux-arm-kernel@lists.infradead.org; Mon, 06 May 2024 11:16:28 +0000 Received: from [192.168.88.20] (91-152-88-126.elisa-laajakaista.fi [91.152.88.126]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id B134D899; Mon, 6 May 2024 13:16:22 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1714994183; bh=5Yf4q20EuBHbQYLGxfSZZAolJNYfiPCEO3OlE+r8l1Q=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=ugF9A9mkOXeI4Ogv2afJcLxHbTlTqvhLVhMjS8WrtbWjrSI+8FFZ/snCNTL3yj9Hx m2vjbba+BVvk9/aCd36naKOqhsY0n2ZSdcd2J83mGvB5jwz7jseF0lCvpyc4X0/3e2 X8ivtnW6pYKntEmUYZWLMBUWaBdkYH+rkCA4rVPY= Message-ID: <363e6d48-3e40-4578-b6f6-17323395b49b@ideasonboard.com> Date: Mon, 6 May 2024 14:16:21 +0300 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [BUG] drm: zynqmp_dp: Lockup in zynqmp_dp_bridge_detect when device is unbound To: Sean Anderson , Laurent Pinchart Cc: Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Daniel Vetter , Michal Simek , dri-devel@lists.freedesktop.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org References: <4d8f4c9b-2efb-4774-9a37-2f257f79b2c9@linux.dev> From: Tomi Valkeinen Content-Language: en-US Autocrypt: addr=tomi.valkeinen@ideasonboard.com; keydata= xsFNBE6ms0cBEACyizowecZqXfMZtnBniOieTuFdErHAUyxVgtmr0f5ZfIi9Z4l+uUN4Zdw2 wCEZjx3o0Z34diXBaMRJ3rAk9yB90UJAnLtb8A97Oq64DskLF81GCYB2P1i0qrG7UjpASgCA Ru0lVvxsWyIwSfoYoLrazbT1wkWRs8YBkkXQFfL7Mn3ZMoGPcpfwYH9O7bV1NslbmyJzRCMO eYV258gjCcwYlrkyIratlHCek4GrwV8Z9NQcjD5iLzrONjfafrWPwj6yn2RlL0mQEwt1lOvn LnI7QRtB3zxA3yB+FLsT1hx0va6xCHpX3QO2gBsyHCyVafFMrg3c/7IIWkDLngJxFgz6DLiA G4ld1QK/jsYqfP2GIMH1mFdjY+iagG4DqOsjip479HCWAptpNxSOCL6z3qxCU8MCz8iNOtZk DYXQWVscM5qgYSn+fmMM2qN+eoWlnCGVURZZLDjg387S2E1jT/dNTOsM/IqQj+ZROUZuRcF7 0RTtuU5q1HnbRNwy+23xeoSGuwmLQ2UsUk7Q5CnrjYfiPo3wHze8avK95JBoSd+WIRmV3uoO rXCoYOIRlDhg9XJTrbnQ3Ot5zOa0Y9c4IpyAlut6mDtxtKXr4+8OzjSVFww7tIwadTK3wDQv Bus4jxHjS6dz1g2ypT65qnHen6mUUH63lhzewqO9peAHJ0SLrQARAQABzTBUb21pIFZhbGtl aW5lbiA8dG9taS52YWxrZWluZW5AaWRlYXNvbmJvYXJkLmNvbT7CwY4EEwEIADgWIQTEOAw+ ll79gQef86f6PaqMvJYe9QUCX/HruAIbAwULCQgHAgYVCgkICwIEFgIDAQIeAQIXgAAKCRD6 PaqMvJYe9WmFD/99NGoD5lBJhlFDHMZvO+Op8vCwnIRZdTsyrtGl72rVh9xRfcSgYPZUvBuT VDxE53mY9HaZyu1eGMccYRBaTLJSfCXl/g317CrMNdY0k40b9YeIX10feiRYEWoDIPQ3tMmA 0nHDygzcnuPiPT68JYZ6tUOvAt7r6OX/litM+m2/E9mtp8xCoWOo/kYO4mOAIoMNvLB8vufi uBB4e/AvAjtny4ScuNV5c5q8MkfNIiOyag9QCiQ/JfoAqzXRjVb4VZG72AKaElwipiKCWEcU R4+Bu5Qbaxj7Cd36M/bI54OrbWWETJkVVSV1i0tghCd6HHyquTdFl7wYcz6cL1hn/6byVnD+ sR3BLvSBHYp8WSwv0TCuf6tLiNgHAO1hWiQ1pOoXyMEsxZlgPXT+wb4dbNVunckwqFjGxRbl Rz7apFT/ZRwbazEzEzNyrBOfB55xdipG/2+SmFn0oMFqFOBEszXLQVslh64lI0CMJm2OYYe3 PxHqYaztyeXsx13Bfnq9+bUynAQ4uW1P5DJ3OIRZWKmbQd/Me3Fq6TU57LsvwRgE0Le9PFQs dcP2071rMTpqTUteEgODJS4VDf4lXJfY91u32BJkiqM7/62Cqatcz5UWWHq5xeF03MIUTqdE qHWk3RJEoWHWQRzQfcx6Fn2fDAUKhAddvoopfcjAHfpAWJ+ENc7BTQROprNHARAAx0aat8GU hsusCLc4MIxOQwidecCTRc9Dz/7U2goUwhw2O5j9TPqLtp57VITmHILnvZf6q3QAho2QMQyE DDvHubrdtEoqaaSKxKkFie1uhWNNvXPhwkKLYieyL9m2JdU+b88HaDnpzdyTTR4uH7wk0bBa KbTSgIFDDe5lXInypewPO30TmYNkFSexnnM3n1PBCqiJXsJahE4ZQ+WnV5FbPUj8T2zXS2xk 0LZ0+DwKmZ0ZDovvdEWRWrz3UzJ8DLHb7blPpGhmqj3ANXQXC7mb9qJ6J/VSl61GbxIO2Dwb xPNkHk8fwnxlUBCOyBti/uD2uSTgKHNdabhVm2dgFNVuS1y3bBHbI/qjC3J7rWE0WiaHWEqy UVPk8rsph4rqITsj2RiY70vEW0SKePrChvET7D8P1UPqmveBNNtSS7In+DdZ5kUqLV7rJnM9 /4cwy+uZUt8cuCZlcA5u8IsBCNJudxEqBG10GHg1B6h1RZIz9Q9XfiBdaqa5+CjyFs8ua01c 9HmyfkuhXG2OLjfQuK+Ygd56mV3lq0aFdwbaX16DG22c6flkkBSjyWXYepFtHz9KsBS0DaZb 4IkLmZwEXpZcIOQjQ71fqlpiXkXSIaQ6YMEs8WjBbpP81h7QxWIfWtp+VnwNGc6nq5IQDESH mvQcsFS7d3eGVI6eyjCFdcAO8eMAEQEAAcLBXwQYAQIACQUCTqazRwIbDAAKCRD6PaqMvJYe 9fA7EACS6exUedsBKmt4pT7nqXBcRsqm6YzT6DeCM8PWMTeaVGHiR4TnNFiT3otD5UpYQI7S suYxoTdHrrrBzdlKe5rUWpzoZkVK6p0s9OIvGzLT0lrb0HC9iNDWT3JgpYDnk4Z2mFi6tTbq xKMtpVFRA6FjviGDRsfkfoURZI51nf2RSAk/A8BEDDZ7lgJHskYoklSpwyrXhkp9FHGMaYII m9EKuUTX9JPDG2FTthCBrdsgWYPdJQvM+zscq09vFMQ9Fykbx5N8z/oFEUy3ACyPqW2oyfvU CH5WDpWBG0s5BALp1gBJPytIAd/pY/5ZdNoi0Cx3+Z7jaBFEyYJdWy1hGddpkgnMjyOfLI7B CFrdecTZbR5upjNSDvQ7RG85SnpYJTIin+SAUazAeA2nS6gTZzumgtdw8XmVXZwdBfF+ICof 92UkbYcYNbzWO/GHgsNT1WnM4sa9lwCSWH8Fw1o/3bX1VVPEsnESOfxkNdu+gAF5S6+I6n3a ueeIlwJl5CpT5l8RpoZXEOVtXYn8zzOJ7oGZYINRV9Pf8qKGLf3Dft7zKBP832I3PQjeok7F yjt+9S+KgSFSHP3Pa4E7lsSdWhSlHYNdG/czhoUkSCN09C0rEK93wxACx3vtxPLjXu6RptBw 3dRq7n+mQChEB1am0BueV1JZaBboIL0AGlSJkm23kw== In-Reply-To: <4d8f4c9b-2efb-4774-9a37-2f257f79b2c9@linux.dev> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240506_041627_600000_A50BE02F X-CRM114-Status: GOOD ( 20.99 ) 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-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Hi, On 04/05/2024 00:54, Sean Anderson wrote: > Hi, > > I have discovered a bug in the displayport driver on drm-misc-next. To > trigger it, run > > echo fd4a0000.display > /sys/bus/platform/drivers/zynqmp-dpsub/unbind > > The system will become unresponsive and (after a bit) splat with a hard > LOCKUP. One core will be unresponsive at the first zynqmp_dp_read in > zynqmp_dp_bridge_detect. > > I believe the issue is due the registers being unmapped and the block > put into reset in zynqmp_dp_remove instead of zynqmp_dpsub_release. This > could be resolved by deferring things until zynqmp_dpsub_release > (requiring us to skip devm_*), or by adding a flag to struct zynqmp_dp > and checking it before each callback. A subsystem-level implementation > might be better for the latter. > > For a better traceback, try applying the below patch and running the > following commands before triggering the lockup: > > echo 4 > /sys/module/drm/parameters/debug > echo 8 > /proc/sys/kernel/printk I wasn't able to reproduce. Where does the detect call come in your case? Looking at the code, afaics, it shouldn't happen. Tomi > diff --git a/drivers/gpu/drm/xlnx/zynqmp_dp.c b/drivers/gpu/drm/xlnx/zynqmp_dp.c > index 9df068a413f3..17b477b14ab5 100644 > --- a/drivers/gpu/drm/xlnx/zynqmp_dp.c > +++ b/drivers/gpu/drm/xlnx/zynqmp_dp.c > @@ -296,6 +296,7 @@ struct zynqmp_dp_config { > * @train_set: set of training data > */ > struct zynqmp_dp { > + unsigned long long magic; > struct device *dev; > struct zynqmp_dpsub *dpsub; > void __iomem *iomem; > @@ -1533,6 +1534,8 @@ static enum drm_connector_status zynqmp_dp_bridge_detect(struct drm_bridge *brid > u32 state, i; > int ret; > > + WARN_ON(dp->magic != 0x0123456789abcdefULL); > + > /* > * This is from heuristic. It takes some delay (ex, 100 ~ 500 msec) to > * get the HPD signal with some monitors. > @@ -1723,6 +1726,7 @@ int zynqmp_dp_probe(struct zynqmp_dpsub *dpsub) > if (!dp) > return -ENOMEM; > > + dp->magic = 0x0123456789abcdefULL; > dp->dev = &pdev->dev; > dp->dpsub = dpsub; > dp->status = connector_status_disconnected; > @@ -1839,4 +1843,5 @@ void zynqmp_dp_remove(struct zynqmp_dpsub *dpsub) > > zynqmp_dp_phy_exit(dp); > zynqmp_dp_reset(dp, true); > + dp->magic = 0xdeadbeefdeadbeefULL; > } _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel