[alsa-devel] [RFC] [PATCH 02/62] mpu401:snd_mpu401_uart_new(): split semantic of irq_flags

Takashi Iwai tiwai at suse.de
Wed Sep 14 11:06:39 CEST 2011

At Wed, 14 Sep 2011 16:49:57 +0800,
Yong Zhang wrote:
> 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 :)

I applied Clemens' patch now to sound git tree.
The temporary location is:

In general, such cross-tree patches should be based on linux-next,
which should contain the latest subsystem tree.  But as kernel.org is
down now, you can check each subsystem tree.



More information about the Alsa-devel mailing list