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: git://github.com/tiwai/sound.git
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.
thanks,
Takashi