From: Thomas Gleixner <tglx@linutronix.de>
To: Jiang Liu <jiang.liu@linux.intel.com>
Cc: "Rafael J . Wysocki" <rjw@rjwysocki.net>,
Bjorn Helgaas <bhelgaas@google.com>,
Lv Zheng <lv.zheng@intel.com>,
LKML <linux-kernel@vger.kernel.org>,
linux-pci@vger.kernel.org, linux-acpi@vger.kernel.org,
"x86 @ kernel . org" <x86@kernel.org>
Subject: Re: [RFC 2/4] PCI, MSI: Optionally free legacy PCI IRQ when enabling MSI/MSI-X
Date: Wed, 20 May 2015 09:47:33 +0200 (CEST) [thread overview]
Message-ID: <alpine.DEB.2.11.1505200947140.4225@nanos> (raw)
In-Reply-To: <555BFA31.5040206@linux.intel.com>
On Wed, 20 May 2015, Jiang Liu wrote:
> On 2015/5/16 5:02, Thomas Gleixner wrote:
> > This is a bit odd. With your proposed change we'll have:
> >
> > alloc_legacy_irq()
> >
> > msi[x]_enable()
> > free_legacy_irq()
> >
> > msi[x]_disable()
> > alloc_legacy_irq()
> Hi Thomas,
> It's for safety. I'm not sure whether the device driver will
> make use of legacy IRQ after calling msi[x]_disable(). I have concerns
> about following pattern in PCI device drivers:
> ---------------------------------------------------
> if (enable_msi() == SUCCESS) {
> if (allocate_resource_for_msi() == SUCCESS)
> return;
> disable_msi();
> }
> use_legacy_irq()
Fair enough.
tglx
next prev parent reply other threads:[~2015-05-20 7:47 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-05-07 3:12 [RFC 0/4] Introduce a mechanism to allocate PCI IRQ on demand Jiang Liu
2015-05-07 3:12 ` [RFC 1/4] PCI: Add hooks to allocate/free IRQ resources when binding/unbinding driver Jiang Liu
2015-05-19 14:45 ` Bjorn Helgaas
2015-05-07 3:12 ` [RFC 2/4] PCI, MSI: Optionally free legacy PCI IRQ when enabling MSI/MSI-X Jiang Liu
2015-05-15 21:02 ` Thomas Gleixner
2015-05-20 3:06 ` Jiang Liu
2015-05-20 7:47 ` Thomas Gleixner [this message]
2015-05-19 15:08 ` Bjorn Helgaas
2015-05-19 15:16 ` Michael S. Tsirkin
2015-05-19 15:26 ` Michael S. Tsirkin
2015-05-20 3:07 ` Jiang Liu
2015-05-19 21:39 ` Bjorn Helgaas
2015-05-20 3:12 ` Jiang Liu
2015-05-07 3:12 ` [RFC 3/4] PCI, x86: Allocate PCI IRQ on demand and free it when not used anymore Jiang Liu
2015-05-07 3:12 ` [RFC 4/4] PCI: Introduce helpers to manage pci_dev->irq and pci_dev->irq_managed Jiang Liu
2015-05-19 13:35 ` [RFC 0/4] Introduce a mechanism to allocate PCI IRQ on demand Thomas Gleixner
2015-05-20 3:21 ` Jiang Liu
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