Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
MIME-Version: 1.0
References: <CAGi-RUJvqJoCXWN2YugRn=WYEk9yzt7m3OPfX_o++PmJWQ3woQ@mail.gmail.com>
In-Reply-To: <CAGi-RUJvqJoCXWN2YugRn=WYEk9yzt7m3OPfX_o++PmJWQ3woQ@mail.gmail.com>
From:   Ramon Fried <rfried.dev@gmail.com>
Date:   Thu, 2 Jan 2020 10:19:49 +0200
Message-ID: <CAGi-RUJuS540oNTtJc1zfv6tbfTtSt-S0m1tdpQ-=5JPeo92xg@mail.gmail.com>
Subject: Re: MSI irqchip configured as IRQCHIP_ONESHOT_SAFE causes spurious IRQs
To:     hkallweit1@gmail.com, Bjorn Helgaas <bhelgaas@google.com>,
        marc.zyngier@arm.com, tglx@linutronix.de, lorenzo.pieralisi@arm.com
Cc:     linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org
Content-Type: text/plain; charset="UTF-8"
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

Ping

On Mon, Dec 9, 2019 at 12:27 PM Ramon Fried <rfried.dev@gmail.com> wrote:
>
> Hi,
> While debugging the root cause of spurious IRQ's on my PCIe MSI line it appears
> that because of the line:
>     info->chip->flags |= IRQCHIP_ONESHOT_SAFE;
> in pci_msi_create_irq_domain()
> The IRQF_ONESHOT is ignored, especially when requesting IRQ through
> pci_request_threaded_irq() where handler is NULL.
>
> The problem is that the MSI masking now only surrounds the HW handler,
> and all additional MSI that occur before the threaded handler is
> complete are considered by the note_interrupt() as spurious.
>
> Besides the side effect of that, I don't really understand the logic
> of not masking the MSI until the threaded handler is complete,
> especially when there's no HW handler and only threaded handler.
>
> Your thoughts?
>
> Thank,
> Ramon.