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Date: Mon, 4 Oct 2010 10:31:18 -0600
From: Grant Likely <grant.likely@secretlab.ca>
To: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Thomas Gleixner <tglx@linutronix.de>,
        "Eric W. Biederman" <ebiederm@xmission.com>,
        LKML <linux-kernel@vger.kernel.org>, linux-arch@vger.kernel.org,
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        David Woodhouse <dwmw2@infradead.org>,
        Jesse Barnes <jbarnes@virtuousgeek.org>,
        Yinghai Lu <yinghai@kernel.org>
Subject: Re: [patch 00/47] Sparse irq rework
Message-ID: <20101004163118.GA13749@angua.secretlab.ca>
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On Mon, Oct 04, 2010 at 09:57:33AM +1100, Benjamin Herrenschmidt wrote:
> On Sun, 2010-10-03 at 21:16 +0200, Thomas Gleixner wrote:
> > 
> > And I really do not see a point to have a truly random 64bit number
> > space for interrupts. Especially the dynamically allocated interrupts
> > (MSI & co) do not care about the number space at all. They care about
> > getting a unique number, nothing else.
> 
> Actually, some implementations care about the actual number... but then,
> at least on powerpc, those are hidden behind the virq translation so we
> really don't care :-)

In fact, if it wasn't for all the embedded platforms where some hard
coded irq number is encoded into the static device tables
(platform_device et al.) I'd argue that the irq number is completely
meaningless outside of the core irq code, and from a device driver
point of view it is just an opaque cookie.

Also from the userspace point of view, the attachment to a particular
irq controller instance is far more interesting than the specific irq
number.

g.