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

Clemens Ladisch clemens at ladisch.de
Thu Sep 8 22:27:43 CEST 2011

Yong Zhang wrote:
> On Thu, Sep 08, 2011 at 03:58:45PM +0200, Clemens Ladisch wrote:
> > ...
> > Here, "no interrupt" and "already reserved" actually mean the same thing,
> > i.e., that the interrupt handling is the responsibility of some other
> > driver.

Sorry, after checking the code, I've realized that my description was
wrong.  irq_flags==0 ("already reserved") means that snd_mpu401_uart_new
should not try to allocate the interrupt, while irq==-1 ("no interrupt")
means that the device never issues mpu401 interrupts, so that the mpu401
code must use a timer to poll the device.

I'll write a patch that changes this function so that irq<0 means
"already reserved", and that "no interrupt" gets another bit in the
info_flags parameter.


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