From: Marc Zyngier <marc.zyngier@arm.com>
To: Mason <slash.tmp@free.fr>, Thomas Gleixner <tglx@linutronix.de>
Cc: Bjorn Helgaas <helgaas@kernel.org>,
Robin Murphy <robin.murphy@arm.com>,
Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
Liviu Dudau <liviu.dudau@arm.com>,
David Laight <david.laight@aculab.com>,
linux-pci <linux-pci@vger.kernel.org>,
Linux ARM <linux-arm-kernel@lists.infradead.org>,
Thibaud Cornic <thibaud_cornic@sigmadesigns.com>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [RFC PATCH v0.2] PCI: Add support for tango PCIe host bridge
Date: Thu, 20 Apr 2017 10:43:11 +0100 [thread overview]
Message-ID: <b61614bd-10e4-25eb-95bc-fd8939d4449f@arm.com> (raw)
In-Reply-To: <2003d851-e17e-1a43-3889-ec6e79e635e3@free.fr>
On 20/04/17 09:20, Mason wrote:
> On 19/04/2017 13:19, Mason wrote:
>
>> My biggest problem is that tango_unmask() is never called.
>
> FTR, the missing incantation was:
> Explicitly calling tango_{mask/unmask/ack} from the corresponding msi_{mask/unmask/ack}
Using irq_chip_mask_parent and co, you mean?
> Marc, I have one nagging doubt, wrt splitting MSI line selection
> and MSI enable.
>
> tango_irq_domain_alloc : finds an available MSI 'j' to allocate
> tango_irq_domain_free : release MSI 'j'
> tango_unmask : enable MSI 'j'
> tango_mask : disable MSI 'j'
>
> Is the following scenario guaranteed to never happen?
>
> tango_irq_domain_alloc // alloc 0
> tango_irq_domain_free // free 0
> tango_irq_domain_alloc // alloc 0
> tango_unmask // enable 0
> tango_unmask // enable 0 = NOP
> tango_mask // disable 0
>
> In this theoretical scenario, we would be left with a non-functional
> MSI 0.
I'm not sure I get the example above, and what the various alloc/free
calls have to do with anything. If you have unbalanced
enable/disable_irq, you loose. Don't do that.
M.
--
Jazz is not dead. It just smells funny...
next prev parent reply other threads:[~2017-04-20 9:44 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-03-23 13:05 [RFC PATCH v0.2] PCI: Add support for tango PCIe host bridge Mason
2017-03-23 14:22 ` Marc Zyngier
2017-03-23 17:03 ` Mason
2017-03-23 23:40 ` Mason
2017-03-24 18:22 ` Marc Zyngier
2017-03-27 14:35 ` Mason
2017-03-27 14:46 ` Thomas Gleixner
2017-03-27 15:18 ` Mason
2017-03-24 18:47 ` Marc Zyngier
2017-03-27 15:53 ` Mason
2017-03-27 17:09 ` Marc Zyngier
2017-03-27 19:44 ` Mason
2017-03-27 21:07 ` Marc Zyngier
2017-03-27 22:04 ` Mason
2017-03-28 8:21 ` Marc Zyngier
2017-04-11 15:13 ` Mason
2017-04-11 15:49 ` Marc Zyngier
2017-04-11 16:26 ` Mason
2017-04-11 16:43 ` Marc Zyngier
2017-04-11 17:52 ` Mason
2017-04-12 8:08 ` Marc Zyngier
2017-04-12 9:50 ` Mason
2017-04-12 9:59 ` Marc Zyngier
2017-04-19 11:19 ` Mason
2017-04-20 8:20 ` Mason
2017-04-20 9:43 ` Marc Zyngier [this message]
2017-03-29 11:39 ` Mason
2017-03-30 11:09 ` Mason
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