Re: linux-4.14.175 broke audio

[Takashi Iwai]

On Thu, 02 Apr 2020 20:06:59 +0200,
Jari Ruusu wrote:
> 
> $ uname -s -r -m
> Linux 4.14.175 x86_64
> $ cat ${HOME}/.config/mpv/mpv.conf
> ao=oss
> vo=opengl
> audio-channels=stereo
> no-msg-color
> $ mpv track18.mp3
> Playing: track18.mp3
>  (+) Audio --aid=1 (mp3)
> [ao/oss] Can't set audio device to s16 output.
> [ao/oss] Can't set audio device to u8 output.
> [ao/oss] Can't set sample format.
> [ao] Failed to initialize audio driver 'oss'
> Could not open/initialize audio device -> no sound.
> Audio: no audio
> 
> 
> Reverting "ALSA: pcm: oss: Avoid plugin buffer overflow"
> upstream commit f2ecf903ef06eb1bbbfa969db9889643d487e73a
> restored audio back to normal working state.

Does the patch below change the behavior?


thanks,

Takashi

---
diff --git a/sound/core/oss/pcm_plugin.c b/sound/core/oss/pcm_plugin.c
index 752d078908e9..50c35ecc8953 100644
--- a/sound/core/oss/pcm_plugin.c
+++ b/sound/core/oss/pcm_plugin.c
@@ -196,7 +196,9 @@ int snd_pcm_plugin_free(struct snd_pcm_plugin *plugin)
 	return 0;
 }
 
-snd_pcm_sframes_t snd_pcm_plug_client_size(struct snd_pcm_substream *plug, snd_pcm_uframes_t drv_frames)
+static snd_pcm_sframes_t plug_client_size(struct snd_pcm_substream *plug,
+					  snd_pcm_uframes_t drv_frames,
+					  bool check_size)
 {
 	struct snd_pcm_plugin *plugin, *plugin_prev, *plugin_next;
 	int stream;
@@ -209,7 +211,7 @@ snd_pcm_sframes_t snd_pcm_plug_client_size(struct snd_pcm_substream *plug, snd_p
 	if (stream == SNDRV_PCM_STREAM_PLAYBACK) {
 		plugin = snd_pcm_plug_last(plug);
 		while (plugin && drv_frames > 0) {
-			if (drv_frames > plugin->buf_frames)
+			if (check_size && drv_frames > plugin->buf_frames)
 				drv_frames = plugin->buf_frames;
 			plugin_prev = plugin->prev;
 			if (plugin->src_frames)
@@ -222,7 +224,7 @@ snd_pcm_sframes_t snd_pcm_plug_client_size(struct snd_pcm_substream *plug, snd_p
 			plugin_next = plugin->next;
 			if (plugin->dst_frames)
 				drv_frames = plugin->dst_frames(plugin, drv_frames);
-			if (drv_frames > plugin->buf_frames)
+			if (check_size && drv_frames > plugin->buf_frames)
 				drv_frames = plugin->buf_frames;
 			plugin = plugin_next;
 		}
@@ -231,7 +233,9 @@ snd_pcm_sframes_t snd_pcm_plug_client_size(struct snd_pcm_substream *plug, snd_p
 	return drv_frames;
 }
 
-snd_pcm_sframes_t snd_pcm_plug_slave_size(struct snd_pcm_substream *plug, snd_pcm_uframes_t clt_frames)
+static snd_pcm_sframes_t plug_slave_size(struct snd_pcm_substream *plug,
+					 snd_pcm_uframes_t clt_frames,
+					 bool check_size)
 {
 	struct snd_pcm_plugin *plugin, *plugin_prev, *plugin_next;
 	snd_pcm_sframes_t frames;
@@ -252,14 +256,14 @@ snd_pcm_sframes_t snd_pcm_plug_slave_size(struct snd_pcm_substream *plug, snd_pc
 				if (frames < 0)
 					return frames;
 			}
-			if (frames > plugin->buf_frames)
+			if (check_size && frames > plugin->buf_frames)
 				frames = plugin->buf_frames;
 			plugin = plugin_next;
 		}
 	} else if (stream == SNDRV_PCM_STREAM_CAPTURE) {
 		plugin = snd_pcm_plug_last(plug);
 		while (plugin) {
-			if (frames > plugin->buf_frames)
+			if (check_size && frames > plugin->buf_frames)
 				frames = plugin->buf_frames;
 			plugin_prev = plugin->prev;
 			if (plugin->src_frames) {
@@ -274,6 +278,18 @@ snd_pcm_sframes_t snd_pcm_plug_slave_size(struct snd_pcm_substream *plug, snd_pc
 	return frames;
 }
 
+snd_pcm_sframes_t snd_pcm_plug_client_size(struct snd_pcm_substream *plug,
+					   snd_pcm_uframes_t drv_frames)
+{
+	return plug_client_size(plug, drv_frames, false);
+}
+
+snd_pcm_sframes_t snd_pcm_plug_slave_size(struct snd_pcm_substream *plug,
+					  snd_pcm_uframes_t clt_frames)
+{
+	return plug_slave_size(plug, clt_frames, false);
+}
+
 static int snd_pcm_plug_formats(const struct snd_mask *mask,
 				snd_pcm_format_t format)
 {
@@ -630,7 +646,7 @@ snd_pcm_sframes_t snd_pcm_plug_write_transfer(struct snd_pcm_substream *plug, st
 		src_channels = dst_channels;
 		plugin = next;
 	}
-	return snd_pcm_plug_client_size(plug, frames);
+	return plug_client_size(plug, frames, true);
 }
 
 snd_pcm_sframes_t snd_pcm_plug_read_transfer(struct snd_pcm_substream *plug, struct snd_pcm_plugin_channel *dst_channels_final, snd_pcm_uframes_t size)
@@ -640,7 +656,7 @@ snd_pcm_sframes_t snd_pcm_plug_read_transfer(struct snd_pcm_substream *plug, str
 	snd_pcm_sframes_t frames = size;
 	int err;
 
-	frames = snd_pcm_plug_slave_size(plug, frames);
+	frames = plug_slave_size(plug, frames, true);
 	if (frames < 0)
 		return frames;