ALSA: usb-audio: Add new quirk FIXED_RATE for JBL Quantum810 Wireless

It seems that the firmware is broken and does not accept
the UAC_EP_CS_ATTR_SAMPLE_RATE URB. There is only one rate (48000Hz)
available in the descriptors for the output endpoint.

Create a new quirk QUIRK_FLAG_FIXED_RATE to skip the rate setup
when only one rate is available (fixed).

BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=216798
Signed-off-by: Jaroslav Kysela <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Takashi Iwai <[e-mail]>

sound/usb/card.h

···
 	bool lowlatency_playback;	/* low-latency playback mode */
 	bool need_setup;		/* (re-)need for hw_params? */
 	bool need_prepare;		/* (re-)need for prepare? */
+	bool fixed_rate;		/* skip rate setup */
 
 	/* for hw constraints */
 	const struct audioformat *cur_audiofmt;

sound/usb/endpoint.c

···
 snd_usb_endpoint_open(struct snd_usb_audio *chip,
 		      const struct audioformat *fp,
 		      const struct snd_pcm_hw_params *params,
-		      bool is_sync_ep)
+		      bool is_sync_ep,
+		      bool fixed_rate)
 {
 	struct snd_usb_endpoint *ep;
 	int ep_num = is_sync_ep ? fp->sync_ep : fp->endpoint;
···
 		ep->implicit_fb_sync = fp->implicit_fb;
 		ep->need_setup = true;
 		ep->need_prepare = true;
+		ep->fixed_rate = fixed_rate;
 
 		usb_audio_dbg(chip, "  channels=%d, rate=%d, format=%s, period_bytes=%d, periods=%d, implicit_fb=%d\n",
 			      ep->cur_channels, ep->cur_rate,
···
 	if (clock && !clock->need_setup)
 		return 0;
 
-	err = snd_usb_init_sample_rate(chip, ep->cur_audiofmt, rate);
-	if (err < 0) {
-		if (clock)
-			clock->rate = 0; /* reset rate */
-		return err;
+	if (!ep->fixed_rate) {
+		err = snd_usb_init_sample_rate(chip, ep->cur_audiofmt, rate);
+		if (err < 0) {
+			if (clock)
+				clock->rate = 0; /* reset rate */
+			return err;
+		}
 	}
 
 	if (clock)

sound/usb/endpoint.h

···
 snd_usb_endpoint_open(struct snd_usb_audio *chip,
 		      const struct audioformat *fp,
 		      const struct snd_pcm_hw_params *params,
-		      bool is_sync_ep);
+		      bool is_sync_ep,
+		      bool fixed_rate);
 void snd_usb_endpoint_close(struct snd_usb_audio *chip,
 			    struct snd_usb_endpoint *ep);
 int snd_usb_endpoint_set_params(struct snd_usb_audio *chip,

sound/usb/implicit.c

···
 #include "usbaudio.h"
 #include "card.h"
 #include "helper.h"
+#include "pcm.h"
 #include "implicit.h"
 
 enum {
···
 snd_usb_find_implicit_fb_sync_format(struct snd_usb_audio *chip,
 				     const struct audioformat *target,
 				     const struct snd_pcm_hw_params *params,
-				     int stream)
+				     int stream,
+				     bool *fixed_rate)
 {
 	struct snd_usb_substream *subs;
 	const struct audioformat *fp, *sync_fmt = NULL;
···
 		}
 	}
 
+	if (fixed_rate)
+		*fixed_rate = snd_usb_pcm_has_fixed_rate(subs);
 	return sync_fmt;
 }
 

sound/usb/implicit.h

···
 snd_usb_find_implicit_fb_sync_format(struct snd_usb_audio *chip,
 				     const struct audioformat *target,
 				     const struct snd_pcm_hw_params *params,
-				     int stream);
+				     int stream, bool *fixed_rate);
 
 #endif /* __USBAUDIO_IMPLICIT_H */

sound/usb/pcm.c

···
 			   true, subs);
 }
 
+bool snd_usb_pcm_has_fixed_rate(struct snd_usb_substream *subs)
+{
+	const struct audioformat *fp;
+	struct snd_usb_audio *chip = subs->stream->chip;
+	int rate = -1;
+
+	if (!(chip->quirk_flags & QUIRK_FLAG_FIXED_RATE))
+		return false;
+	list_for_each_entry(fp, &subs->fmt_list, list) {
+		if (fp->rates & SNDRV_PCM_RATE_CONTINUOUS)
+			return false;
+		if (fp->nr_rates < 1)
+			continue;
+		if (fp->nr_rates > 1)
+			return false;
+		if (rate < 0) {
+			rate = fp->rate_table[0];
+			continue;
+		}
+		if (rate != fp->rate_table[0])
+			return false;
+	}
+	return true;
+}
+
 static int init_pitch_v1(struct snd_usb_audio *chip, int ep)
 {
 	struct usb_device *dev = chip->dev;
···
 	struct snd_usb_audio *chip = subs->stream->chip;
 	const struct audioformat *fmt;
 	const struct audioformat *sync_fmt;
+	bool fixed_rate, sync_fixed_rate;
 	int ret;
 
 	ret = snd_media_start_pipeline(subs);
 	if (ret)
 		return ret;
 
+	fixed_rate = snd_usb_pcm_has_fixed_rate(subs);
 	fmt = find_substream_format(subs, hw_params);
 	if (!fmt) {
 		usb_audio_dbg(chip,
···
 	if (fmt->implicit_fb) {
 		sync_fmt = snd_usb_find_implicit_fb_sync_format(chip, fmt,
 								hw_params,
-								!substream->stream);
+								!substream->stream,
+								&sync_fixed_rate);
 		if (!sync_fmt) {
 			usb_audio_dbg(chip,
 				      "cannot find sync format: ep=0x%x, iface=%d:%d, format=%s, rate=%d, channels=%d\n",
···
 		}
 	} else {
 		sync_fmt = fmt;
+		sync_fixed_rate = fixed_rate;
 	}
 
 	ret = snd_usb_lock_shutdown(chip);
···
 		close_endpoints(chip, subs);
 	}
 
-	subs->data_endpoint = snd_usb_endpoint_open(chip, fmt, hw_params, false);
+	subs->data_endpoint = snd_usb_endpoint_open(chip, fmt, hw_params, false, fixed_rate);
 	if (!subs->data_endpoint) {
 		ret = -EINVAL;
 		goto unlock;
···
 	if (fmt->sync_ep) {
 		subs->sync_endpoint = snd_usb_endpoint_open(chip, sync_fmt,
 							    hw_params,
-							    fmt == sync_fmt);
+							    fmt == sync_fmt,
+							    sync_fixed_rate);
 		if (!subs->sync_endpoint) {
 			ret = -EINVAL;
 			goto unlock;

sound/usb/pcm.h

···
 int snd_usb_pcm_suspend(struct snd_usb_stream *as);
 int snd_usb_pcm_resume(struct snd_usb_stream *as);
 
+bool snd_usb_pcm_has_fixed_rate(struct snd_usb_substream *as);
+
 int snd_usb_init_pitch(struct snd_usb_audio *chip,
 		       const struct audioformat *fmt);
 void snd_usb_preallocate_buffer(struct snd_usb_substream *subs);

sound/usb/quirks.c

···
 		   QUIRK_FLAG_GENERIC_IMPLICIT_FB),
 	DEVICE_FLG(0x0525, 0xa4ad, /* Hamedal C20 usb camero */
 		   QUIRK_FLAG_IFACE_SKIP_CLOSE),
+	DEVICE_FLG(0x0ecb, 0x2069, /* JBL Quantum810 Wireless */
+		   QUIRK_FLAG_FIXED_RATE),
 
 	/* Vendor matches */
 	VENDOR_FLG(0x045e, /* MS Lifecam */

sound/usb/usbaudio.h

···
  * QUIRK_FLAG_FORCE_IFACE_RESET
  *  Force an interface reset whenever stopping & restarting a stream
  *  (e.g. after xrun)
+ * QUIRK_FLAG_FIXED_RATE
+ *  Do not set PCM rate (frequency) when only one rate is available
+ *  for the given endpoint.
  */
 
 #define QUIRK_FLAG_GET_SAMPLE_RATE	(1U << 0)
···
 #define QUIRK_FLAG_SKIP_IMPLICIT_FB	(1U << 18)
 #define QUIRK_FLAG_IFACE_SKIP_CLOSE	(1U << 19)
 #define QUIRK_FLAG_FORCE_IFACE_RESET	(1U << 20)
+#define QUIRK_FLAG_FIXED_RATE		(1U << 21)
 
 #endif /* __USBAUDIO_H */