ALSA: docs: Add description about ack callback -EPIPE error handling

Add a brief description about the newly added behavior of the PCM ack callback with -EPIPE error. Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Takashi Iwai <[email protected]>
katyo · Mar 24, 2023 · f84af10 · f84af10
1 parent 0146878
commit f84af10
Showing 1 changed file with 4 additions and 0 deletions.
diff --git a/Documentation/sound/kernel-api/writing-an-alsa-driver.rst b/Documentation/sound/kernel-api/writing-an-alsa-driver.rst
@@ -2137,6 +2137,10 @@ This callback is also not mandatory. This callback is called when the
 emu10k1-fx and cs46xx need to track the current ``appl_ptr`` for the
 internal buffer, and this callback is useful only for such a purpose.
 
+The callback function may return 0 or a negative error. When the
+return value is ``-EPIPE``, PCM core treats as a buffer XRUN happens,
+and changes the state to ``SNDRV_PCM_STATE_XRUN`` automatically.
+
 This callback is atomic as default.
 
 page callback