[PATCH 1/3] ALSA: docs: Add description of usb-audio playback_urb_fixup quirk

We missed the description for the recently introduced quirk bit
QUIRK_FLAG_PLAYBACK_URB_FIXUP.  A brief explanation is added here.

Signed-off-by: Takashi Iwai <[email protected]>
---
 Documentation/sound/alsa-configuration.rst | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/Documentation/sound/alsa-configuration.rst b/Documentation/sound/alsa-configuration.rst
index c4aef14a3147..b2171472e6cb 100644
--- a/Documentation/sound/alsa-configuration.rst
+++ b/Documentation/sound/alsa-configuration.rst
@@ -2401,6 +2401,11 @@ quirk_flags
           disabling GET_CUR instead of the whole mixer. The current volume will
           then be provided by the internal cache that stores the last set
           volume
+        * bit 31: ``playback_urb_fixup``
+          Some devices show the stuttering at playback, and this quirk
+          works around it by enforcing the fixed max URBs (12) instead of
+          the dynamic calculation from the buffer size, and passing the
+          `URB_ISO_ASAP` URB flag.
 
 This module supports multiple devices, autoprobe and hotplugging.
 
-- 
2.55.0