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From: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
To: Trent Piepho <tpiepho@impinj.com>
Cc: "marc.zyngier@arm.com" <marc.zyngier@arm.com>,
	"gustavo.pimentel@synopsys.com" <gustavo.pimentel@synopsys.com>,
	"joao.pinto@synopsys.com" <joao.pinto@synopsys.com>,
	"jingoohan1@gmail.com" <jingoohan1@gmail.com>,
	"linux-pci@vger.kernel.org" <linux-pci@vger.kernel.org>,
	"faiz_abbas@ti.com" <faiz_abbas@ti.com>,
	"stable@vger.kernel.org" <stable@vger.kernel.org>,
	"bhelgaas@google.com" <bhelgaas@google.com>,
	"vigneshr@ti.com" <vigneshr@ti.com>
Subject: Re: [PATCH] PCI: dwc: Fix interrupt race in when handling MSI
Date: Tue, 13 Nov 2018 10:36:46 +0000	[thread overview]
Message-ID: <20181113103646.GA11202@e107981-ln.cambridge.arm.com> (raw)
In-Reply-To: <1542071920.30311.411.camel@impinj.com>

On Tue, Nov 13, 2018 at 01:18:41AM +0000, Trent Piepho wrote:

[...]

> > Based on the information provided, its very likely that I should use the
> > PCIE_MSI_INTR0_MASK register instead of PCIE_MSI_INTR0_ENABLE on the
> > dw_pci_bottom_mask() and dw_pci_bottom_unmask() callbacks. As soon as I return
> > from Linux plumbers conference, I will test the system using the
> > PCIE_MSI_INTR0_MASK register.
> 
> Using enable to mask the interrupt is broken.  It will allow an MSI to
> be lost if it arrives while the MSI in not enabled.  It is impossible
> to prevent that from racing against the pci device driver's final check
> that no MSI-signaled condition in the hardware is present.

That's exactly why I raised the point. I would like to understand if
this means that this revert is not enough to fix the underlying issue
or we need this revert AND correct mask/unmask operations.

Thanks,
Lorenzo

  reply	other threads:[~2018-11-13 10:36 UTC|newest]

Thread overview: 32+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-10-27  0:00 [PATCH] PCI: dwc: Fix interrupt race in when handling MSI Trent Piepho
2018-11-05 10:28 ` Vignesh R
2018-11-05 12:08 ` Gustavo Pimentel
2018-11-06 14:53 ` Lorenzo Pieralisi
2018-11-06 16:00   ` Marc Zyngier
2018-11-06 19:40     ` Trent Piepho
2018-11-07 11:07       ` Lorenzo Pieralisi
2018-11-07 12:58         ` Gustavo Pimentel
2018-11-07 18:41       ` Marc Zyngier
2018-11-07 20:17         ` Trent Piepho
2018-11-08  9:49           ` Marc Zyngier
2018-11-08 19:49             ` Trent Piepho
2018-11-09 10:13               ` Lorenzo Pieralisi
2018-11-09 17:17                 ` Vignesh R
2018-11-09 11:34               ` Marc Zyngier
2018-11-09 18:53                 ` Trent Piepho
2018-11-13  0:41                 ` Gustavo Pimentel
2018-11-13  1:18                   ` Trent Piepho
2018-11-13 10:36                     ` Lorenzo Pieralisi [this message]
2018-11-13 18:55                       ` Trent Piepho
2018-11-13 14:40                   ` Marc Zyngier
2018-11-07 12:57     ` Gustavo Pimentel
2018-11-07 18:32       ` Trent Piepho
2018-11-08 11:46         ` Gustavo Pimentel
2018-11-08 20:51           ` Trent Piepho
2018-11-12 16:01             ` Lorenzo Pieralisi
2018-11-13  1:03               ` Gustavo Pimentel
2018-11-14 21:29               ` Trent Piepho
2018-11-12 23:45             ` Gustavo Pimentel
2018-11-07 18:46       ` Marc Zyngier
2018-11-08 11:24         ` Gustavo Pimentel
2018-11-06 18:59   ` Trent Piepho

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