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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id E926FCCA485 for ; Tue, 28 Jun 2022 14:09:01 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 7303B10E5D3; Tue, 28 Jun 2022 14:08:53 +0000 (UTC) Received: from mga07.intel.com (mga07.intel.com [134.134.136.100]) by gabe.freedesktop.org (Postfix) with ESMTPS id C4F1F8929B; Tue, 28 Jun 2022 14:08:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1656425331; x=1687961331; h=date:from:to:cc:message-id:in-reply-to:references: mime-version:content-transfer-encoding:resent-date: resent-from:subject:resent-message-id:resent-to; bh=NlN93CPLmTbVnxPPhc+BVfuBiZgxZ+dnkYTe/LYS/gQ=; b=GQFp4GSMz9aZsJu51arHOXiSc917AQpi6WBE1e4nVvydAmiIMOBLm7hm 1ObneK1tIPaJfOu630qcEi9ksKWUh7Ggel96xi4mLHBYh3l7LiNTJ6+qk km1qo9fL1RsgNVQf3kZuHv+DRl5N3gl+tR1O1/ZdatZs68AyKL7/e66Fj np2DYK12fXqB0yL6BaWGcHDpmgBkB/HPqe5RzB15ADRjgxyljoVWiECn9 K3yL05MtXyhsEq4bFZfU5zGgczqM5DFZN9NCTXIcm0R6AJ2Gm66wIOAFm /oaVwwfjXm9PPxNop6OIwI+ORH2G7JteqsrJnS2snbV+Dp+F8Dqhps2pp Q==; X-IronPort-AV: E=McAfee;i="6400,9594,10391"; a="345747145" X-IronPort-AV: E=Sophos;i="5.92,227,1650956400"; d="scan'208";a="345747145" Received: from fmsmga007.fm.intel.com ([10.253.24.52]) by orsmga105.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 28 Jun 2022 07:08:51 -0700 X-IronPort-AV: E=Sophos;i="5.92,227,1650956400"; d="scan'208";a="594809580" Received: from maurocar-mobl2.ger.corp.intel.com (HELO maurocar-mobl2) ([10.252.40.41]) by fmsmga007-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 28 Jun 2022 07:08:44 -0700 Date: Mon, 27 Jun 2022 11:00:56 +0200 From: Mauro Carvalho Chehab (by way of Mauro Carvalho Chehab ) To: Tvrtko Ursulin Message-ID: <20220627110056.6dfa4f9b@maurocar-mobl2> In-Reply-To: <160e613f-a0a8-18ff-5d4b-249d4280caa8@linux.intel.com> References: <5ee647f243a774927ec328bfca8212abc4957909.1655306128.git.mchehab@kernel.org> <160e613f-a0a8-18ff-5d4b-249d4280caa8@linux.intel.com> X-Mailer: Claws Mail 4.1.0 (GTK 3.24.34; x86_64-redhat-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Resent-Date: Tue, 28 Jun 2022 16:08:42 +0200 Resent-From: Mauro Carvalho Chehab Resent-Message-ID: <20220628160842.59a9bd94@maurocar-mobl2> Resent-To: , , , , , , , , , , , , , , , , , , , , , , , , Subject: Re: [Intel-gfx] [PATCH 5/6] drm/i915/gt: Serialize GRDOM access between multiple engine resets X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: David Airlie , dri-devel@lists.freedesktop.org, Chris Wilson , Chris Wilson , Dave Airlie , Thomas =?UTF-8?B?SGVs?= =?UTF-8?B?bHN0csO2bQ==?= , intel-gfx@lists.freedesktop.org, Thomas Hellstrom , Rodrigo Vivi , Mauro Carvalho Chehab , linux-kernel@vger.kernel.org, stable@vger.kernel.org, Tejas Upadhyay Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" Hi Tvrtko, On Fri, 24 Jun 2022 09:34:21 +0100 Tvrtko Ursulin wrote: > On 23/06/2022 12:17, Andi Shyti wrote: > > Hi Mauro, > >=20 > > On Wed, Jun 15, 2022 at 04:27:39PM +0100, Mauro Carvalho Chehab wrote: = =20 > >> From: Chris Wilson > >> > >> Don't allow two engines to be reset in parallel, as they would both > >> try to select a reset bit (and send requests to common registers) > >> and wait on that register, at the same time. Serialize control of > >> the reset requests/acks using the uncore->lock, which will also ensure > >> that no other GT state changes at the same time as the actual reset. > >> > >> Fixes: 7938d61591d3 ("drm/i915: Flush TLBs before releasing backing st= ore") > >> > >> Reported-by: Mika Kuoppala > >> Signed-off-by: Chris Wilson > >> Cc: Mika Kuoppala > >> Cc: Andi Shyti > >> Cc: stable@vger.kernel.org > >> Acked-by: Thomas Hellstr=C3=B6m > >> Signed-off-by: Mauro Carvalho Chehab =20 > >=20 > > Reviewed-by: Andi Shyti =20 >=20 > Notice I had a bunch of questions and asks in this series so please do=20 > not merge until those are addressed. >=20 > In this particular patch (and some others) for instance Fixes: tag, at=20 > least against that sha, shouldn't be there. Hmm... I sent an answer to your points, but I can't see it at: https://lore.kernel.org/all/160e613f-a0a8-18ff-5d4b-249d4280caa8@linux.int= el.com/ Maybe it got lost somewhere, I dunno. Yeah, indeed the fixes tag on patch 5/6 should be removed as this is not directly related to changeset 7938d61591d3. Yet, this one is required for patch 6 to work. The other patches on this series, though, are modifying the code=20 introduced by changeset 7938d61591d3. Patch 2 is clearly a workaround needed for TLB cache invalidation to work on some GPUs. So, while not related to Broadwell, they're also fixing some TLB cache issues. So, IMO, it should keep the fixes. I tried to port just the two serialize patches to drm-tip, in order to solve the issues on Broadwell, but it didn't work, as the logic=20 inside the spinlock could be calling schedule() with a spinlock hold: =20 Jun 14 17:38:48 silver kernel: [ 23.227813] BUG: sleeping function calle= d from invalid context at drivers/gpu/drm/i915/intel_uncore.c:2496 Jun 14 17:38:48 silver kernel: [ 23.227816] in_atomic(): 1, irqs_disable= d(): 1, non_block: 0, pid: 37, name: kworker/u8:1 Jun 14 17:38:48 silver kernel: [ 23.227818] preempt_count: 1, expected: 0 Jun 14 17:38:48 silver kernel: [ 23.227819] RCU nest depth: 0, expected:= 0 Jun 14 17:38:48 silver kernel: [ 23.227820] 5 locks held by kworker/u8:1= /37: Jun 14 17:38:48 silver kernel: [ 23.227822] #0: ffff88811159b538 ((wq_c= ompletion)i915){+.+.}-{0:0}, at: process_one_work+0x1e0/0x580 Jun 14 17:38:48 silver kernel: [ 23.227831] #1: ffffc90000183e60 ((work= _completion)(&(&i915->mm.free_work)->work)){+.+.}-{0:0}, at: process_one_wo= rk+0x1e0/0x580 Jun 14 17:38:48 silver kernel: [ 23.227837] #2: ffff88811b34c5e8 (reser= vation_ww_class_mutex){+.+.}-{3:3}, at: __i915_gem_free_objects+0xba/0x210 = [i915] Jun 14 17:38:48 silver kernel: [ 23.228283] #3: ffff88810a66c2d8 (>->= tlb_invalidate_lock){+.+.}-{3:3}, at: intel_gt_invalidate_tlbs+0xe7/0x4d0 [= i915] Jun 14 17:38:48 silver kernel: [ 23.228663] #4: ffff88810a668f28 (&unco= re->lock){-.-.}-{2:2}, at: intel_gt_invalidate_tlbs+0x115/0x4d0 [i915] I didn't investigate the root cause, but it seems related to PM, so=20 patches 1 and 3 seem to be required for the serialization logic to actually work. So, I would keep the Fixes: tag mentioning changeset 7938d61591d3 on patches: 1, 2, 3 and 6. Yet, IMO the entire series should be merged on -stable. If that's OK for you and there's no additional issues to be addressed, I'll submit a v2 of this series removing the Fixes tag from patches 4 and 5. Regards, Mauro