From: Ingo Molnar <mingo@elte.hu>
To: Milton Miller <miltonm@bga.com>
Cc: Thomas Gleixner <tglx@linutronix.de>,
linux-kernel@vger.kernel.org,
Grant Likely <grant.likely@secretlab.ca>
Subject: Re: [PATCH RFC 4/4] irq: allow a per-allocation upper limit when allocating irqs
Date: Wed, 25 May 2011 09:55:17 +0200 [thread overview]
Message-ID: <20110525075517.GC21552@elte.hu> (raw)
In-Reply-To: <alloc-irq-range-v2@mdm.bga.com>
* Milton Miller <miltonm@bga.com> wrote:
> Allow the option to specify an upper limit to the irq numbers for
> each allocation. The limit is non-inclusive, and 0 means no limit
> needed by caller.
>
> Some irq chips can support a relative large and arbitrary range,
> but not infinite. For example, they may use the linux irq number
> as the msi desciptor data, which for msi is 16 bits.
>
> Since e7bcecb7b1 (genirq: Make nr_irqs runtime expandable), checking
> NR_IRQS or even nr_irqs is not sufficient to enforce such requirements
> when sparse irqs are configured.
Would be nice to add some more background info to the changelog, like what bad
things happen if this change is not provided and what good things would happen
if it is provided.
Thanks,
Ingo
next prev parent reply other threads:[~2011-05-25 7:55 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <generic-irq-changes@mdm.bga.com>
2011-05-25 6:34 ` [PATCH RFC 4/4] irq: allow a per-allocation upper limit when allocating irqs Milton Miller
2011-05-25 7:55 ` Ingo Molnar [this message]
2011-05-25 8:32 ` Thomas Gleixner
2011-05-27 3:38 ` Grant Likely
2011-05-25 6:34 ` [PATCH 3/4] irq: remove unnecessary __ref on irq_alloc_descs Milton Miller
2011-05-25 6:34 ` [PATCH 2/4] irq: radix_tree_insert can fail Milton Miller
2011-05-25 8:18 ` Thomas Gleixner
2011-05-25 10:48 ` Milton Miller
2011-05-25 6:34 ` [PATCH 1/4] sparse irq: protect irq_to_desc against irq_free_descs Milton Miller
2011-05-25 8:14 ` Thomas Gleixner
2011-05-25 10:49 ` Milton Miller
2011-05-25 10:54 ` Thomas Gleixner
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