Hello Jaroslav Kysela,

The patch fd28941cff1c: "ALSA: usb-audio: Add new quirk FIXED_RATE for JBL Quantum810 Wireless" from Dec 15, 2022, leads to the following Smatch static checker warning:

sound/usb/pcm.c:543 snd_usb_hw_params() error: uninitialized symbol 'sync_fixed_rate'.

sound/usb/pcm.c 471 static int snd_usb_hw_params(struct snd_pcm_substream *substream, 472 struct snd_pcm_hw_params *hw_params) 473 { 474 struct snd_usb_substream *subs = substream->runtime->private_data; 475 struct snd_usb_audio *chip = subs->stream->chip; 476 const struct audioformat *fmt; 477 const struct audioformat *sync_fmt; 478 bool fixed_rate, sync_fixed_rate; 479 int ret; 480 481 ret = snd_media_start_pipeline(subs); 482 if (ret) 483 return ret; 484 485 fixed_rate = snd_usb_pcm_has_fixed_rate(subs); 486 fmt = find_substream_format(subs, hw_params); 487 if (!fmt) { 488 usb_audio_dbg(chip, 489 "cannot find format: format=%s, rate=%d, channels=%d\n", 490 snd_pcm_format_name(params_format(hw_params)), 491 params_rate(hw_params), params_channels(hw_params)); 492 ret = -EINVAL; 493 goto stop_pipeline; 494 } 495 496 if (fmt->implicit_fb) { 497 sync_fmt = snd_usb_find_implicit_fb_sync_format(chip, fmt, 498 hw_params, 499 !substream->stream, 500 &sync_fixed_rate);

"sync_fixed_rate" is uninitialized when we "Use the original audioformat as fallback for the shared altset" and find_matching_substream() returns NULL.

501 if (!sync_fmt) { 502 usb_audio_dbg(chip, 503 "cannot find sync format: ep=0x%x, iface=%d:%d, format=%s, rate=%d, channels=%d\n", 504 fmt->sync_ep, fmt->sync_iface, 505 fmt->sync_altsetting, 506 snd_pcm_format_name(params_format(hw_params)), 507 params_rate(hw_params), params_channels(hw_params)); 508 ret = -EINVAL; 509 goto stop_pipeline; 510 } 511 } else { 512 sync_fmt = fmt; 513 sync_fixed_rate = fixed_rate; 514 } 515 516 ret = snd_usb_lock_shutdown(chip); 517 if (ret < 0) 518 goto stop_pipeline; 519 520 ret = snd_usb_pcm_change_state(subs, UAC3_PD_STATE_D0); 521 if (ret < 0) 522 goto unlock; 523 524 if (subs->data_endpoint) { 525 if (snd_usb_endpoint_compatible(chip, subs->data_endpoint, 526 fmt, hw_params)) 527 goto unlock; 528 if (stop_endpoints(subs, false)) 529 sync_pending_stops(subs); 530 close_endpoints(chip, subs); 531 } 532 533 subs->data_endpoint = snd_usb_endpoint_open(chip, fmt, hw_params, false, fixed_rate); 534 if (!subs->data_endpoint) { 535 ret = -EINVAL; 536 goto unlock; 537 } 538 539 if (fmt->sync_ep) { 540 subs->sync_endpoint = snd_usb_endpoint_open(chip, sync_fmt, 541 hw_params, 542 fmt == sync_fmt, --> 543 sync_fixed_rate); 544 if (!subs->sync_endpoint) { 545 ret = -EINVAL; 546 goto unlock; 547 }

regards, dan carpenter