[alsa-devel] [PATCH v4 11/15] ALSA: usb-audio: remove altset_idx from snd_usb_substream

[Eldad Zack]

We only need to check the current altsetting in one place, so there's no
benefit from tracking it.
This patch replaces that one check with get_cur_altset_idx() added in
a previous patch and in the proc substream dump routine.

Thanks to Clemens Ladisch for pointing out the difference between
altset_idx and altsetting - the check is changed accordingly to match
against fmt->altsetting.

Note that the proc dump now returns the altsetting number and not the
array index.

This allows removing altset_idx from snd_usb_substream.

Signed-off-by: Eldad Zack <eldad at fogrefinery.com>

---
v2: corrected check.
---
 sound/usb/card.h | 1 -
 sound/usb/pcm.c  | 8 ++------
 sound/usb/pcm.h  | 2 ++
 sound/usb/proc.c | 4 +++-
 4 files changed, 7 insertions(+), 8 deletions(-)

diff --git a/sound/usb/card.h b/sound/usb/card.h
index 7ccacb4..eb38b0a 100644
--- a/sound/usb/card.h
+++ b/sound/usb/card.h
@@ -120,7 +120,6 @@ struct snd_usb_substream {
 	unsigned int period_bytes;	/* current period bytes (for hw_params callback) */
 	unsigned int period_frames;	/* current frames per period */
 	unsigned int buffer_periods;	/* current periods per buffer */
-	unsigned int altset_idx;     /* USB data format: index of alternate setting */
 	unsigned int txfr_quirk:1;	/* allow sub-frame alignment */
 	unsigned int fmt_type;		/* USB audio format type (1-3) */
 	unsigned int pkt_offset_adj;	/* Bytes to drop from beginning of packets (for non-compliant devices) */
diff --git a/sound/usb/pcm.c b/sound/usb/pcm.c
index 7895c81..8854ee5 100644
--- a/sound/usb/pcm.c
+++ b/sound/usb/pcm.c
@@ -216,7 +216,7 @@ int snd_usb_init_pitch(struct snd_usb_audio *chip, int iface,
 	}
 }
 
-static int get_cur_altsetting(struct usb_device *dev, int ifnum)
+int get_cur_altsetting(struct usb_device *dev, int ifnum)
 {
 	struct usb_interface *iface;
 	struct usb_interface_descriptor *altsd;
@@ -527,12 +527,11 @@ static int set_format(struct snd_usb_substream *subs, struct audioformat *fmt)
 				dev->devnum, fmt->iface, fmt->altsetting, err);
 			return -EIO;
 		}
-		subs->altset_idx = 0;
 	}
 
 	/* set interface */
 	if (subs->interface != fmt->iface ||
-	    subs->altset_idx != fmt->altset_idx) {
+	    get_cur_altsetting(subs->dev, subs->interface) != fmt->altsetting) {
 		err = subs_set_interface(subs, fmt->iface, fmt->altsetting);
 		if (err < 0) {
 			snd_printk(KERN_ERR "%d:%d:%d: usb_set_interface failed (%d)\n",
@@ -541,7 +540,6 @@ static int set_format(struct snd_usb_substream *subs, struct audioformat *fmt)
 		}
 		snd_printdd(KERN_INFO "setting usb interface %d:%d\n",
 				fmt->iface, fmt->altsetting);
-		subs->altset_idx = fmt->altset_idx;
 
 		snd_usb_set_interface_quirk(dev);
 	}
@@ -783,7 +781,6 @@ static int snd_usb_hw_params(struct snd_pcm_substream *substream,
 		return ret;
 
 	subs->interface = fmt->iface;
-	subs->altset_idx = fmt->altset_idx;
 	subs->need_setup_ep = true;
 
 	return 0;
@@ -1267,7 +1264,6 @@ static int snd_usb_pcm_open(struct snd_pcm_substream *substream, int direction)
 	struct snd_usb_substream *subs = &as->substream[direction];
 
 	subs->interface = -1;
-	subs->altset_idx = 0;
 	runtime->hw = snd_usb_hardware;
 	runtime->private_data = subs;
 	subs->pcm_substream = substream;
diff --git a/sound/usb/pcm.h b/sound/usb/pcm.h
index df7a003..0c9cb8c 100644
--- a/sound/usb/pcm.h
+++ b/sound/usb/pcm.h
@@ -10,5 +10,7 @@ int snd_usb_init_pitch(struct snd_usb_audio *chip, int iface,
 		       struct usb_host_interface *alts,
 		       struct audioformat *fmt);
 
+int get_cur_altsetting(struct usb_device *dev, int ifnum);
+
 
 #endif /* __USBAUDIO_PCM_H */
diff --git a/sound/usb/proc.c b/sound/usb/proc.c
index 5f761ab..ab6aafe 100644
--- a/sound/usb/proc.c
+++ b/sound/usb/proc.c
@@ -27,6 +27,7 @@
 #include "card.h"
 #include "endpoint.h"
 #include "proc.h"
+#include "pcm.h"
 
 /* convert our full speed USB rate into sampling rate in Hz */
 static inline unsigned get_full_speed_hz(unsigned int usb_rate)
@@ -140,7 +141,8 @@ static void proc_dump_substream_status(struct snd_usb_substream *subs, struct sn
 	if (subs->running) {
 		snd_iprintf(buffer, "  Status: Running\n");
 		snd_iprintf(buffer, "    Interface = %d\n", subs->interface);
-		snd_iprintf(buffer, "    Altset = %d\n", subs->altset_idx);
+		snd_iprintf(buffer, "    Altset = %d\n",
+			    get_cur_altsetting(subs->dev, subs->interface));
 		proc_dump_ep_status(subs, subs->data_endpoint, subs->sync_endpoint, buffer);
 	} else {
 		snd_iprintf(buffer, "  Status: Stop\n");
-- 
1.8.1.5