All of lore.kernel.org
 help / color / mirror / Atom feed
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...

WARNING: multiple messages have this Message-ID (diff)
From: marc.zyngier@arm.com (Marc Zyngier)
To: linux-arm-kernel@lists.infradead.org
Subject: [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...

  reply	other threads:[~2017-04-20  9:44 UTC|newest]

Thread overview: 59+ 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 13:05 ` Mason
2017-03-23 14:22 ` Marc Zyngier
2017-03-23 14:22   ` Marc Zyngier
2017-03-23 17:03   ` Mason
2017-03-23 17:03     ` Mason
2017-03-23 23:40     ` Mason
2017-03-23 23:40       ` Mason
2017-03-24 18:22       ` Marc Zyngier
2017-03-24 18:22         ` Marc Zyngier
2017-03-27 14:35         ` Mason
2017-03-27 14:35           ` Mason
2017-03-27 14:35           ` Mason
2017-03-27 14:46           ` Thomas Gleixner
2017-03-27 14:46             ` Thomas Gleixner
2017-03-27 15:18             ` Mason
2017-03-27 15:18               ` Mason
2017-03-27 15:18               ` Mason
2017-03-24 18:47     ` Marc Zyngier
2017-03-24 18:47       ` Marc Zyngier
2017-03-27 15:53       ` Mason
2017-03-27 15:53         ` Mason
2017-03-27 17:09         ` Marc Zyngier
2017-03-27 17:09           ` Marc Zyngier
2017-03-27 19:44           ` Mason
2017-03-27 19:44             ` Mason
2017-03-27 21:07             ` Marc Zyngier
2017-03-27 21:07               ` Marc Zyngier
2017-03-27 21:07               ` Marc Zyngier
2017-03-27 22:04               ` Mason
2017-03-27 22:04                 ` Mason
2017-03-28  8:21                 ` Marc Zyngier
2017-03-28  8:21                   ` Marc Zyngier
2017-04-11 15:13           ` Mason
2017-04-11 15:13             ` Mason
2017-04-11 15:49             ` Marc Zyngier
2017-04-11 15:49               ` Marc Zyngier
2017-04-11 16:26               ` Mason
2017-04-11 16:26                 ` Mason
2017-04-11 16:43                 ` Marc Zyngier
2017-04-11 16:43                   ` Marc Zyngier
2017-04-11 17:52                   ` Mason
2017-04-11 17:52                     ` Mason
2017-04-12  8:08                     ` Marc Zyngier
2017-04-12  8:08                       ` Marc Zyngier
2017-04-12  9:50                       ` Mason
2017-04-12  9:50                         ` Mason
2017-04-12  9:59                         ` Marc Zyngier
2017-04-12  9:59                           ` Marc Zyngier
2017-04-19 11:19                           ` Mason
2017-04-19 11:19                             ` Mason
2017-04-20  8:20                             ` Mason
2017-04-20  8:20                               ` Mason
2017-04-20  9:43                               ` Marc Zyngier [this message]
2017-04-20  9:43                                 ` Marc Zyngier
2017-03-29 11:39 ` Mason
2017-03-29 11:39   ` Mason
2017-03-30 11:09 ` Mason
2017-03-30 11:09   ` Mason

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=b61614bd-10e4-25eb-95bc-fd8939d4449f@arm.com \
    --to=marc.zyngier@arm.com \
    --cc=david.laight@aculab.com \
    --cc=helgaas@kernel.org \
    --cc=linux-arm-kernel@lists.infradead.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-pci@vger.kernel.org \
    --cc=liviu.dudau@arm.com \
    --cc=lorenzo.pieralisi@arm.com \
    --cc=robin.murphy@arm.com \
    --cc=slash.tmp@free.fr \
    --cc=tglx@linutronix.de \
    --cc=thibaud_cornic@sigmadesigns.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.