[ALSA] rawmidi: adjust runtime->avail when changing output buffer size

Modules: RawMidi Midlevel

When the output buffer size is changed, runtime->avail must be
adjusted to the new size; otherwise, draining of a bigger buffer would
appear to fail because avail does not reach buffer_size.
Signed-off-by: NClemens Ladisch <clemens@ladisch.de>

sound/core/rawmidi.c

@@ -635,6 +635,7 @@ int snd_rawmidi_output_params(struct snd_rawmidi_substream *substream,
 		kfree(runtime->buffer);
 		runtime->buffer = newbuf;
 		runtime->buffer_size = params->buffer_size;
+		runtime->avail = runtime->buffer_size;
 	}
 	runtime->avail_min = params->avail_min;
 	substream->active_sensing = !params->no_active_sensing;