summaryrefslogtreecommitdiffstats
path: root/Documentation
diff options
context:
space:
mode:
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/DocBook/writing-an-alsa-driver.tmpl36
1 files changed, 21 insertions, 15 deletions
diff --git a/Documentation/DocBook/writing-an-alsa-driver.tmpl b/Documentation/DocBook/writing-an-alsa-driver.tmpl
index 598c22f3b3ac..5de23c007078 100644
--- a/Documentation/DocBook/writing-an-alsa-driver.tmpl
+++ b/Documentation/DocBook/writing-an-alsa-driver.tmpl
@@ -4288,7 +4288,7 @@ struct _snd_pcm_runtime {
<![CDATA[
struct snd_rawmidi *rmidi;
snd_mpu401_uart_new(card, 0, MPU401_HW_MPU401, port, info_flags,
- irq, irq_flags, &rmidi);
+ irq, &rmidi);
]]>
</programlisting>
</informalexample>
@@ -4343,6 +4343,13 @@ struct _snd_pcm_runtime {
by itself to start processing the output stream in the irq handler.
</para>
+ <para>
+ If the MPU-401 interface shares its interrupt with the other logical
+ devices on the card, set <constant>MPU401_INFO_IRQ_HOOK</constant>
+ (see <link linkend="midi-interface-interrupt-handler"><citetitle>
+ below</citetitle></link>).
+ </para>
+
<para>
Usually, the port address corresponds to the command port and
port + 1 corresponds to the data port. If not, you may change
@@ -4375,14 +4382,12 @@ struct _snd_pcm_runtime {
</para>
<para>
- The 6th argument specifies the irq number for UART. If the irq
- is already allocated, pass 0 to the 7th argument
- (<parameter>irq_flags</parameter>). Otherwise, pass the flags
- for irq allocation
- (<constant>SA_XXX</constant> bits) to it, and the irq will be
- reserved by the mpu401-uart layer. If the card doesn't generate
- UART interrupts, pass -1 as the irq number. Then a timer
- interrupt will be invoked for polling.
+ The 6th argument specifies the ISA irq number that will be
+ allocated. If no interrupt is to be allocated (because your
+ code is already allocating a shared interrupt, or because the
+ device does not use interrupts), pass -1 instead.
+ For a MPU-401 device without an interrupt, a polling timer
+ will be used instead.
</para>
</section>
@@ -4390,12 +4395,13 @@ struct _snd_pcm_runtime {
<title>Interrupt Handler</title>
<para>
When the interrupt is allocated in
- <function>snd_mpu401_uart_new()</function>, the private
- interrupt handler is used, hence you don't have anything else to do
- than creating the mpu401 stuff. Otherwise, you have to call
- <function>snd_mpu401_uart_interrupt()</function> explicitly when
- a UART interrupt is invoked and checked in your own interrupt
- handler.
+ <function>snd_mpu401_uart_new()</function>, an exclusive ISA
+ interrupt handler is automatically used, hence you don't have
+ anything else to do than creating the mpu401 stuff. Otherwise, you
+ have to set <constant>MPU401_INFO_IRQ_HOOK</constant>, and call
+ <function>snd_mpu401_uart_interrupt()</function> explicitly from your
+ own interrupt handler when it has determined that a UART interrupt
+ has occurred.
</para>
<para>