From: Mikhail Gavrilov Date: Tue, 28 Jul 2026 22:22:39 +0000 (+0500) Subject: ALSA: usb-audio: Add GET_SAMPLE_RATE quirk for C-Media CM6206 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=e93bb6f3acec5b70a5567efe78f1a96148a7291f;p=thirdparty%2Flinux.git ALSA: usb-audio: Add GET_SAMPLE_RATE quirk for C-Media CM6206 The C-Media CM6206 (0d8c:0102) truncates the three-byte sample rate it returns for UAC_GET_CUR to its two low bytes. After the rate has been set to 96000 (0x017700) the device reports back 30464 (0x007700). At probe time the driver initializes every altsetting to its maximum rate, so altsetting 5 is set to 96000 and the warning appears on each plug-in, before anything has opened the device: usb 3-1.3: 1:5 Set sample rate 96000, clock 0 usb 3-1.3: current rate 30464 is different from the runtime rate 96000 That altsetting is the one parse_audio_format_rates_v1() already fixes up for this chip, so this affects every CM6206. Only the read-back is broken, the rate itself is applied: a 1 kHz sine rendered at 96 kHz is recovered at 1000.2 Hz, and a silent fallback to 48000 would have been reported as 0x00bb80 rather than as the low half of the requested rate. Add a QUIRK_FLAG_GET_SAMPLE_RATE entry for the device so the read-back is skipped. Setting the same flag through the quirk_flags module parameter makes the warning disappear while the 96000 init still happens. Signed-off-by: Mikhail Gavrilov Link: https://patch.msgid.link/20260728222239.62749-1-mikhail.v.gavrilov@gmail.com Signed-off-by: Takashi Iwai --- diff --git a/sound/usb/quirks.c b/sound/usb/quirks.c index 40aa40fccb46..d2a111ee50ab 100644 --- a/sound/usb/quirks.c +++ b/sound/usb/quirks.c @@ -2347,6 +2347,8 @@ static const struct usb_audio_quirk_flags_table quirk_flags_table[] = { QUIRK_FLAG_MIXER_PLAYBACK_MIN_MUTE), DEVICE_FLG(0x0d8c, 0x0014, /* C-Media */ QUIRK_FLAG_CTL_MSG_DELAY_1M | QUIRK_FLAG_MIXER_PLAYBACK_MIN_MUTE), + DEVICE_FLG(0x0d8c, 0x0102, /* C-Media CM6206 */ + QUIRK_FLAG_GET_SAMPLE_RATE), DEVICE_FLG(0x0e0b, 0xfa01, /* Feaulle Rainbow */ QUIRK_FLAG_GET_SAMPLE_RATE | QUIRK_FLAG_MIXER_PLAYBACK_MIN_MUTE), DEVICE_FLG(0x0ecb, 0x205c, /* JBL Quantum610 Wireless */