From mboxrd@z Thu Jan 1 00:00:00 1970 From: Heiko Stuebner Subject: Re: [PATCH 2/2] iommu/rockchip: Move irq request past pm_runtime_enable Date: Tue, 07 Aug 2018 13:45:26 +0200 Message-ID: <2114757.JfhfUCyzvi@phil> References: <20180807085406.3863-1-marc.zyngier@arm.com> <20180807085406.3863-3-marc.zyngier@arm.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20180807085406.3863-3-marc.zyngier-5wv7dgnIgG8@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org Errors-To: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org To: Marc Zyngier Cc: Jeffy Chen , linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-rockchip-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org List-Id: iommu@lists.linux-foundation.org Am Dienstag, 7. August 2018, 10:54:06 CEST schrieb Marc Zyngier: > Enabling the interrupt early, before power has been applied to the > device, can result in an interrupt being delivered too early if: > > - the IOMMU shares an interrupt with a VOP > - the VOP has a pending interrupt (after a kexec, for example) > > In these conditions, we end-up taking the interrupt without > the IOMMU being ready to handle the interrupt (not powered on). > > Moving the interrupt request past the pm_runtime_enable() call > makes sure we can at least access the IOMMU registers. Note that > this is only a partial fix, and that the VOP interrupt will still > be screaming until the VOP driver kicks in, which advocates for > a more synchronized interrupt enabling/disabling approach. > > Fixes: 0f181d3cf7d98 ("iommu/rockchip: Add runtime PM support") > Signed-off-by: Marc Zyngier Reviewed-by: Heiko Stuebner From mboxrd@z Thu Jan 1 00:00:00 1970 From: heiko@sntech.de (Heiko Stuebner) Date: Tue, 07 Aug 2018 13:45:26 +0200 Subject: [PATCH 2/2] iommu/rockchip: Move irq request past pm_runtime_enable In-Reply-To: <20180807085406.3863-3-marc.zyngier@arm.com> References: <20180807085406.3863-1-marc.zyngier@arm.com> <20180807085406.3863-3-marc.zyngier@arm.com> Message-ID: <2114757.JfhfUCyzvi@phil> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Am Dienstag, 7. August 2018, 10:54:06 CEST schrieb Marc Zyngier: > Enabling the interrupt early, before power has been applied to the > device, can result in an interrupt being delivered too early if: > > - the IOMMU shares an interrupt with a VOP > - the VOP has a pending interrupt (after a kexec, for example) > > In these conditions, we end-up taking the interrupt without > the IOMMU being ready to handle the interrupt (not powered on). > > Moving the interrupt request past the pm_runtime_enable() call > makes sure we can at least access the IOMMU registers. Note that > this is only a partial fix, and that the VOP interrupt will still > be screaming until the VOP driver kicks in, which advocates for > a more synchronized interrupt enabling/disabling approach. > > Fixes: 0f181d3cf7d98 ("iommu/rockchip: Add runtime PM support") > Signed-off-by: Marc Zyngier Reviewed-by: Heiko Stuebner 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=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,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 94E76C46471 for ; Tue, 7 Aug 2018 11:45:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 56F93214FA for ; Tue, 7 Aug 2018 11:45:37 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 56F93214FA Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=sntech.de Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389177AbeHGN7c (ORCPT ); Tue, 7 Aug 2018 09:59:32 -0400 Received: from gloria.sntech.de ([185.11.138.130]:50632 "EHLO gloria.sntech.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726902AbeHGN7b (ORCPT ); Tue, 7 Aug 2018 09:59:31 -0400 Received: from wd0970.dip.tu-dresden.de ([141.76.111.202] helo=phil.localnet) by gloria.sntech.de with esmtpsa (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.89) (envelope-from ) id 1fn0QY-00060H-NA; Tue, 07 Aug 2018 13:45:26 +0200 From: Heiko Stuebner To: Marc Zyngier Cc: linux-arm-kernel@lists.infradead.org, linux-rockchip@lists.infradead.org, iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org, Joerg Roedel , Jeffy Chen Subject: Re: [PATCH 2/2] iommu/rockchip: Move irq request past pm_runtime_enable Date: Tue, 07 Aug 2018 13:45:26 +0200 Message-ID: <2114757.JfhfUCyzvi@phil> In-Reply-To: <20180807085406.3863-3-marc.zyngier@arm.com> References: <20180807085406.3863-1-marc.zyngier@arm.com> <20180807085406.3863-3-marc.zyngier@arm.com> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Am Dienstag, 7. August 2018, 10:54:06 CEST schrieb Marc Zyngier: > Enabling the interrupt early, before power has been applied to the > device, can result in an interrupt being delivered too early if: > > - the IOMMU shares an interrupt with a VOP > - the VOP has a pending interrupt (after a kexec, for example) > > In these conditions, we end-up taking the interrupt without > the IOMMU being ready to handle the interrupt (not powered on). > > Moving the interrupt request past the pm_runtime_enable() call > makes sure we can at least access the IOMMU registers. Note that > this is only a partial fix, and that the VOP interrupt will still > be screaming until the VOP driver kicks in, which advocates for > a more synchronized interrupt enabling/disabling approach. > > Fixes: 0f181d3cf7d98 ("iommu/rockchip: Add runtime PM support") > Signed-off-by: Marc Zyngier Reviewed-by: Heiko Stuebner