From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Return-Path: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII; format=flowed Date: Thu, 01 Mar 2018 21:17:47 +0530 From: poza@codeaurora.org To: Bjorn Helgaas Cc: Bjorn Helgaas , Philippe Ombredanne , Thomas Gleixner , Greg Kroah-Hartman , Kate Stewart , linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, Dongdong Liu , Keith Busch , Wei Zhang , Sinan Kaya , Timur Tabi Subject: Re: [PATCH] PCI/DPC: Fix INT legacy interrupt in dpc_irq In-Reply-To: <20180301153802.GD13722@bhelgaas-glaptop.roam.corp.google.com> References: <1517415535-21850-1-git-send-email-poza@codeaurora.org> <20180301153802.GD13722@bhelgaas-glaptop.roam.corp.google.com> Message-ID: List-ID: On 2018-03-01 21:08, Bjorn Helgaas wrote: > Hi Oza, > > On Wed, Jan 31, 2018 at 09:48:55PM +0530, Oza Pawandeep wrote: >> Current dpc driver acknowledge the interrupt in deferred work, which >> works >> okay since LPI are edge triggered. >> But when RP does not have MSI support, port service driver falls back >> to >> legacy GIC SPI interrupts, and with current code we do not acknowledge >> the >> interrupt and we get dpc interrupt storm. >> This patch acknowledges the interrupt in interrupt handler. > > Would you mind rephrasing this changelog in generic PCIe terms? E.g., > "LPI" and "GIC SPI" are meaningless to me (I assume they're > arm64-specific things), but I don't think it's any arm64-specific > thing that motivates this change. IIUC, the issue should occur any > time we're not using MSI, so we should be able to describe it in > purely PCIe terms. > > s/dpc/DPC/ in text. > > It looks like this changelog is intended to be multiple paragraphs; if > so, please leave a blank line between them. It's a little awkward to > infer "this is a new paragraph" from the fact that "the previous line > didn't look full" :) > > Please rebase to my "master" branch (v4.16-rc1). There was some minor > change that made this not apply cleanly. > sure will do these changes and re-post the same. Regards, Oza. >> Signed-off-by: Oza Pawandeep >> >> diff --git a/drivers/pci/pcie/pcie-dpc.c b/drivers/pci/pcie/pcie-dpc.c >> index 2d976a6..570b561 100644 >> --- a/drivers/pci/pcie/pcie-dpc.c >> +++ b/drivers/pci/pcie/pcie-dpc.c >> @@ -134,7 +134,7 @@ static void interrupt_event_handler(struct >> work_struct *work) >> } >> >> pci_write_config_word(pdev, dpc->cap_pos + PCI_EXP_DPC_STATUS, >> - PCI_EXP_DPC_STATUS_TRIGGER | PCI_EXP_DPC_STATUS_INTERRUPT); >> + PCI_EXP_DPC_STATUS_TRIGGER); >> } >> >> static void dpc_rp_pio_print_tlp_header(struct device *dev, >> @@ -277,6 +277,8 @@ static irqreturn_t dpc_irq(int irq, void *context) >> >> schedule_work(&dpc->work); >> } >> + pci_write_config_word(pdev, dpc->cap_pos + PCI_EXP_DPC_STATUS, >> + PCI_EXP_DPC_STATUS_INTERRUPT); >> return IRQ_HANDLED; >> } >> >> -- >> Qualcomm Datacenter Technologies, Inc. as an affiliate of Qualcomm >> Technologies, Inc., >> a Qualcomm Technologies, Inc. is a member of the Code Aurora Forum, a >> Linux Foundation Collaborative Project. >>