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=-8.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING, SPF_HELO_NONE,SPF_PASS 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 C8BA8C432BE for ; Thu, 26 Aug 2021 06:35:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 99EFC610CB for ; Thu, 26 Aug 2021 06:35:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239471AbhHZGga (ORCPT ); Thu, 26 Aug 2021 02:36:30 -0400 Received: from mga06.intel.com ([134.134.136.31]:22551 "EHLO mga06.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238082AbhHZGg3 (ORCPT ); Thu, 26 Aug 2021 02:36:29 -0400 X-IronPort-AV: E=McAfee;i="6200,9189,10087"; a="278689519" X-IronPort-AV: E=Sophos;i="5.84,352,1620716400"; d="asc'?scan'208";a="278689519" Received: from fmsmga003.fm.intel.com ([10.253.24.29]) by orsmga104.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 25 Aug 2021 23:35:25 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.84,352,1620716400"; d="asc'?scan'208";a="527640870" Received: from zhen-hp.sh.intel.com (HELO zhen-hp) ([10.239.160.143]) by FMSMGA003.fm.intel.com with ESMTP; 25 Aug 2021 23:35:18 -0700 Date: Thu, 26 Aug 2021 14:12:19 +0800 From: Zhenyu Wang To: Luis Chamberlain Cc: Christoph Hellwig , Jason Gunthorpe , "dri-devel@lists.freedesktop.org" , Greg KH , "intel-gfx@lists.freedesktop.org" , Joonas Lahtinen , "linux-kernel@vger.kernel.org" , Jani Nikula , Gerd Hoffmann , "Vivi, Rodrigo" , "intel-gvt-dev@lists.freedesktop.org" , "Wang, Zhi A" , Jani Nikula Subject: Re: refactor the i915 GVT support Message-ID: <20210826061219.GD9942@zhen-hp.sh.intel.com> Reply-To: Zhenyu Wang References: <20210729072022.GB31896@lst.de> <20210803094315.GF13928@zhen-hp.sh.intel.com> <20210803143058.GA1721383@nvidia.com> <20210804052606.GG13928@zhen-hp.sh.intel.com> <20210816173458.GA9183@lst.de> <20210817010851.GW13928@zhen-hp.sh.intel.com> <20210817052203.GX13928@zhen-hp.sh.intel.com> <20210819082929.GB13928@zhen-hp.sh.intel.com> <20210820141724.GA29034@lst.de> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="GZVR6ND4mMseVXL/" Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --GZVR6ND4mMseVXL/ Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On 2021.08.20 12:56:34 -0700, Luis Chamberlain wrote: > On Fri, Aug 20, 2021 at 04:17:24PM +0200, Christoph Hellwig wrote: > > On Thu, Aug 19, 2021 at 04:29:29PM +0800, Zhenyu Wang wrote: > > > I'm working on below patch to resolve this. But I met a weird issue in > > > case when building i915 as module and also kvmgt module, it caused > > > busy wait on request_module("kvmgt") when boot, it doesn't happen if > > > building i915 into kernel. I'm not sure what could be the reason? > >=20 > > Luis, do you know if there is a problem with a request_module from > > a driver ->probe routine that is probably called by a module_init > > function itself? >=20 > Generally no, but you can easily foot yourself in the feet by creating > cross dependencies and not dealing with them properly. I'd make sure > to keep module initialization as simple as possible, and run whatever > takes more time asynchronously, then use a state machine to allow > you to verify where you are in the initialization phase or query it > or wait for a completion with a timeout. >=20 > It seems the code in question is getting some spring cleaning, and its > unclear where the code is I can inspect. If there's a tree somewhere I > can take a peak I'd be happy to review possible oddities that may stick > out. I tried to put current patches under test here: https://github.com/intel/gv= t-linux/tree/gvt-staging The issue can be produced with CONFIG_DRM_I915=3Dm and CONFIG_DRM_I915_GVT_= KVMGT=3Dm. >=20 > My goto model for these sorts of problems is to abstract the issue > *outside* of the driver in question and implement new selftests to > try to reproduce. This serves two purposes, 1) helps with testing > 2) may allow you to see the problem more clearly. >=20 I'll see if can abstract that. Thanks, Luis. --GZVR6ND4mMseVXL/ Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iF0EARECAB0WIQTXuabgHDW6LPt9CICxBBozTXgYJwUCYScwwwAKCRCxBBozTXgY J4yKAJ0d9jcEa21+qw9af0hJvQT2LXk0WACggn/GD2G8nFh6SY4kc8+7qqXkpi0= =fIjO -----END PGP SIGNATURE----- --GZVR6ND4mMseVXL/--