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=-16.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,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 F2D49C433C1 for ; Tue, 23 Mar 2021 15:13:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D0C56619C6 for ; Tue, 23 Mar 2021 15:13:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232541AbhCWPNJ (ORCPT ); Tue, 23 Mar 2021 11:13:09 -0400 Received: from mail.kernel.org ([198.145.29.99]:42148 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232727AbhCWPMw (ORCPT ); Tue, 23 Mar 2021 11:12:52 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id E4C0D619C1; Tue, 23 Mar 2021 15:12:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1616512372; bh=MA5YBPu4rtGbm7rfCEilpagOMIGhJYvOgD2AucgSTSo=; h=Date:From:To:Cc:Subject:In-Reply-To:From; b=MCNlVU8Yu70hYWf7k0X11tlXsyrhmM/QJftKF8IrKxCWPO2DCbylZhY3uwVBLFnml 121MQ9zbkdXeXo4oiMVY+PDG5cmRjxZ/TVK3nz0+iUHm5pVcZ5knOKJv11jvusCYdi 2kNbJd2auV/YCtIK37nmXaZCHckoCFI0f7CKExpcodOm/MZ0QRuO0A0hRRqixlQLZM rW68zoR44+iFK2EgAPUWOuVOQlAwkVWvebBa6G2feN0/3qLeu7ffkfeLshzKT3efEY PMQY8IZH/zicmuvdNSI+DUypl1PCvGpgBYjaHF+MgiZNwPq/asi4xEXz9RHG2rerM0 cdPoQzn9JLwYw== Date: Tue, 23 Mar 2021 10:12:50 -0500 From: Bjorn Helgaas To: Jisheng Zhang Cc: Jingoo Han , Gustavo Pimentel , Lorenzo Pieralisi , Rob Herring , Bjorn Helgaas , linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, Kishon Vijay Abraham I , Richard Zhu , Lucas Stach Subject: Re: [PATCH RESEND] PCI: dwc: Fix MSI not work after resume Message-ID: <20210323151250.GA576016@bjorn-Precision-5520> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210323110115.3740f6b1@xhacker.debian> Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org [-cc Dilip (mail to him bounced)] On Tue, Mar 23, 2021 at 11:01:15AM +0800, Jisheng Zhang wrote: > On Mon, 22 Mar 2021 20:24:41 -0500 Bjorn Helgaas wrote: > > > > [+cc Kishon, Richard, Lucas, Dilip] > > > > On Mon, Mar 01, 2021 at 11:10:31AM +0800, Jisheng Zhang wrote: > > > After we move dw_pcie_msi_init() into core -- dw_pcie_host_init(), the > > > MSI stops working after resume. Because dw_pcie_host_init() is only > > > called once during probe. To fix this issue, we move dw_pcie_msi_init() > > > to dw_pcie_setup_rc(). > > > > This patch looks fine, but I don't think the commit log tells the > > whole story. > > > > Prior to 59fbab1ae40e, it looks like the only dwc-based drivers with > > resume functions were dra7xx, imx6, intel-gw, and tegra [1]. > > > > Only tegra called dw_pcie_msi_init() in the resume path, and I do > > think 59fbab1ae40e broke MSI after resume because it removed the > > dw_pcie_msi_init() call from tegra_pcie_enable_msi_interrupts(). > > > > I'm not convinced this patch fixes it reliably, though. The call > > chain looks like this: > > > > tegra_pcie_dw_resume_noirq > > tegra_pcie_dw_start_link > > if (dw_pcie_wait_for_link(pci)) > > dw_pcie_setup_rc > > > > dw_pcie_wait_for_link() returns 0 if the link is up, so we only call > > dw_pcie_setup_rc() in the case where the link *didn't* come up. If > > the link comes up nicely without retry, we won't call > > dw_pcie_setup_rc() and hence won't call dw_pcie_msi_init(). > > The v1 version patch was sent before commit 275e88b06a (PCI: tegra: Fix host > link initialization"). At that time, the resume path looks like this: > > tegra_pcie_dw_resume_noirq > tegra_pcie_dw_host_init > tegra_pcie_prepare_host > dw_pcie_setup_rc > > so after patch, dw_pcie_msi_init() will be called. But now it seems that > the tegra version needs one more fix for the resume. > > So could I sent a new patch to update the commit-msg a bit? This patch only touches the dwc core, and the commit log says generically that it fixes MSI after resume, so one could assume that it applies to all dwc-based drivers. But I don't think it's that simple, so I'd like to know *which* drivers are fixed and which commits are related. I don't see how 59fbab1ae40e breaks anything except tegra. > > Since then, exynos added a resume function. My guess is MSI never > > worked after resume for dra7xx, exynos, imx6, and intel-gw because > > they don't call dw_pcie_msi_init() in their resume functions. > > > > This patch looks like it should fix MSI after resume for exynos, imx6, > > and intel-gw because they *do* call dw_pcie_setup_rc() from their > > resume functions [2], and after this patch, dw_pcie_msi_init() will be > > called from there. > > > > I suspect MSI after resume still doesn't work on dra7xx. > > I checked the dra7xx history, I'm afraid that the resume never works > from the beginning if the host lost power during suspend, I guess the > platform never power off the host but only the phy? Sounds like that would make sense. > > [1] git grep -A20 -e "static.*resume_noirq" 59fbab1ae40e^:drivers/pci/controller/dwc > > [2] git grep -A20 -e "static.*resume_noirq" drivers/pci/controller/dwc > > > > > Fixes: 59fbab1ae40e ("PCI: dwc: Move dw_pcie_msi_init() into core") > > > Reviewed-by: Rob Herring > > > Signed-off-by: Jisheng Zhang > > > --- > > > Since v1: > > > - collect Reviewed-by tag > > > > > > drivers/pci/controller/dwc/pcie-designware-host.c | 3 ++- > > > 1 file changed, 2 insertions(+), 1 deletion(-) > > > > > > diff --git a/drivers/pci/controller/dwc/pcie-designware-host.c b/drivers/pci/controller/dwc/pcie-designware-host.c > > > index 7e55b2b66182..e6c274f4485c 100644 > > > --- a/drivers/pci/controller/dwc/pcie-designware-host.c > > > +++ b/drivers/pci/controller/dwc/pcie-designware-host.c > > > @@ -400,7 +400,6 @@ int dw_pcie_host_init(struct pcie_port *pp) > > > } > > > > > > dw_pcie_setup_rc(pp); > > > - dw_pcie_msi_init(pp); > > > > > > if (!dw_pcie_link_up(pci) && pci->ops && pci->ops->start_link) { > > > ret = pci->ops->start_link(pci); > > > @@ -551,6 +550,8 @@ void dw_pcie_setup_rc(struct pcie_port *pp) > > > } > > > } > > > > > > + dw_pcie_msi_init(pp); > > > + > > > /* Setup RC BARs */ > > > dw_pcie_writel_dbi(pci, PCI_BASE_ADDRESS_0, 0x00000004); > > > dw_pcie_writel_dbi(pci, PCI_BASE_ADDRESS_1, 0x00000000); > > > -- > > > 2.30.1 > > > >