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Message-ID: <20110914084957.GB23710@zhy>
Date: Wed, 14 Sep 2011 16:49:57 +0800
From: Yong Zhang <yong.zhang0@...il.com>
To: Clemens Ladisch <clemens@...isch.de>
Cc: Takashi Iwai <tiwai@...e.de>, linux-kernel@...r.kernel.org,
Jaroslav Kysela <perex@...ex.cz>, alsa-devel@...a-project.org
Subject: Re: [RFC] [PATCH 02/62] mpu401:snd_mpu401_uart_new(): split semantic
of irq_flags
On Tue, Sep 13, 2011 at 11:24:41AM +0200, Clemens Ladisch wrote:
[snip]
>
> completely untested:
>
> --8<---------------------------------------------------------------->8--
> ALSA: mpu401: clean up interrupt specification
>
> The semantics of snd_mpu401_uart_new()'s interrupt parameters are
> somewhat counterintuitive: To prevent the function from allocating its
> own interrupt, either the irq number must be invalid, or the irq_flags
> parameter must be zero. At the same time, the irq parameter being
> invalid specifies that the mpu401 code has to work without an interrupt
> allocated by the caller. This implies that, if there is an interrupt
> and it is allocated by the caller, the irq parameter must be set to
> a valid-looking number which then isn't actually used.
>
> With the removal of IRQF_DISABLED, zero becomes a valid irq_flags value,
> which forces us to handle the parameters differently.
>
> This patch introduces a new flag MPU401_INFO_IRQ_HOOK for when the
> device interrupt is handled by the caller, and makes the allocation of
> the interrupt to depend only on the irq parameter. As suggested by
> Takashi, the irq_flags parameter was dropped because, when used, it had
> the constant value IRQF_DISABLED.
Thanks Clemens. Your patch will eventually save much lines from mine ,
actually I only need to touch request_irq() in snd_mpu401_uart_new().
But do you have any idea by which tree this patch will go to mainline?
Thus I could make a new patch based on it :)
Thanks,
Yong
>
> Signed-off-by: Clemens Ladisch <clemens@...isch.de>
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