linux-kernel - Re: [PATCH v3] PCI: hosts: mark pcie/pci (msi) irq cascade handler as IRQF_NO

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Date:	Wed, 13 Jan 2016 11:50:16 -0600
From:	Bjorn Helgaas <helgaas@...nel.org>
To:	Sebastian Andrzej Siewior <bigeasy@...utronix.de>
Cc:	Grygorii Strashko <grygorii.strashko@...com>,
	linux-pci@...r.kernel.org, Bjorn Helgaas <bhelgaas@...gle.com>,
	tony@...mide.com, nsekhar@...com,
	linux-arm-kernel@...ts.infradead.org,
	linux-samsung-soc@...r.kernel.org, linux-tegra@...r.kernel.org,
	linux-sh@...r.kernel.org, linux-omap@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	Kishon Vijay Abraham I <kishon@...com>,
	Jingoo Han <jingoohan1@...il.com>,
	Kukjin Kim <kgene@...nel.org>,
	Krzysztof Kozlowski <k.kozlowski@...sung.com>,
	Richard Zhu <Richard.Zhu@...escale.com>,
	Lucas Stach <l.stach@...gutronix.de>,
	Thierry Reding <thierry.reding@...il.com>,
	Stephen Warren <swarren@...dotorg.org>,
	Alexandre Courbot <gnurou@...il.com>,
	Simon Horman <horms@...ge.net.au>,
	Pratyush Anand <pratyush.anand@...il.com>,
	Michal Simek <michal.simek@...inx.com>,
	Sören Brinkmann <soren.brinkmann@...inx.com>
Subject: Re: [PATCH v3] PCI: hosts: mark pcie/pci (msi) irq cascade handler
 as IRQF_NO_THREAD

On Wed, Jan 13, 2016 at 02:39:04PM +0100, Sebastian Andrzej Siewior wrote:
> * Bjorn Helgaas | 2016-01-06 16:18:27 [-0600]:
> 
> >Hi Bjorn,
> 
> >> diff --git a/drivers/pci/host/pci-dra7xx.c b/drivers/pci/host/pci-dra7xx.c
> >> index 8c36880..0415192 100644
> >> --- a/drivers/pci/host/pci-dra7xx.c
> >> +++ b/drivers/pci/host/pci-dra7xx.c
> >> @@ -301,8 +301,19 @@ static int __init dra7xx_add_pcie_port(struct dra7xx_pcie *dra7xx,
> >>  		return -EINVAL;
> >>  	}
> >>  
> >> +	/*
> >> +	 * Mark dra7xx_pcie_msi IRQ as IRQF_NO_THREAD
> >> +	 * On -RT and if kernel is booting with "threadirqs" cmd line parameter
> >> +	 * the dra7xx_pcie_msi_irq_handler() will be forced threaded but,
> >> +	 * in the same time, it's IRQ dispatcher and calls generic_handle_irq(),
> >> +	 * which, in turn, will be resolved to handle_simple_irq() call.
> >> +	 * The handle_simple_irq() expected to be called with IRQ disabled, as
> >> +	 * result kernle will display warning:
> >> +	 * "irq XXX handler YYY+0x0/0x14 enabled interrupts".
> >> +	 */
> 
> could you _please_ remove this coment? This kind of comment (if at all)
> should be part of the commit message (which is the case more or less).

IIRC, Grygorii specifically wanted to keep this comment in dra7xx, but
I do agree that this level of detail is more appropriate for a changelog.

If Grygorii and Kishon don't object, I can update the patch to remove it.

> >>  	ret = devm_request_irq(&pdev->dev, pp->irq,
> >> -			       dra7xx_pcie_msi_irq_handler, IRQF_SHARED,
> >> +			       dra7xx_pcie_msi_irq_handler,
> >> +			       IRQF_SHARED | IRQF_NO_THREAD,
> >>  			       "dra7-pcie-msi",	pp);
> >>  	if (ret) {
> >>  		dev_err(&pdev->dev, "failed to request irq\n");
> >> diff --git a/drivers/pci/host/pci-exynos.c b/drivers/pci/host/pci-exynos.c
> 
> Sebastian
> --
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