At Wed, 28 Jun 2006 14:23:23 -0400,
Lee Revell wrote:
>
> On Wed, 2006-06-28 at 20:16 +0200, Takashi Iwai wrote:
> > At Wed, 28 Jun 2006 14:06:59 -0400,
> > Lee Revell wrote:
> > >
> > > I'm writing a MIDI driver for hardware that is not available yet, so for
> > > now I'm just doing simulation. To simulate MIDI input I just use a
> > > timer that calls snd_rawmidi_receive(substream_input, &dummy_data, 1).
> > >
> > > Is it normal for the MIDI input trigger callback to be called over and
> > > over in a loop when I run "arecordmidi"? Or should it only be called
> > > once, when the stream is opened?
> >
> > It's normal. The driver should remember that the device was already
> > triggered and just ignore the succeeding trigger call or do some
> > useful thing (for example, mpu401_uart peeks the input FIFO for
> > hardwares that don't support proper input irq).
>
> OK, great.
>
> I ask because I am working off of emumpu401.c as an example, which does:
>
> static void
> snd_emu10k1_midi_input_trigger(struct snd_rawmidi_substream *substream,
> int up)
> {
> [...]
> if (up)
> snd_emu10k1_intr_enable(emu, midi->rx_enable);
> else
> snd_emu10k1_intr_disable(emu, midi->rx_enable);
> }
>
> And it seemed kind of wrong that the EMU driver would enable RX
> interrupts over and over while recording.
>
> I guess it just means the EMU driver is not as efficient as it could
> be? ;-)
Yeah, it can be optimized to check the current value :)
Takashi
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