From: Hector Martin Date: Mon, 10 Aug 2020 08:24:00 +0000 (+0900) Subject: ALSA: usb-audio: work around streaming quirk for MacroSilicon MS2109 X-Git-Tag: v4.4.233~34 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=6743ddb78a705d9695ad0379068d4183bd877956;p=thirdparty%2Fkernel%2Fstable.git ALSA: usb-audio: work around streaming quirk for MacroSilicon MS2109 commit 1b7ecc241a67ad6b584e071bd791a54e0cd5f097 upstream. Further investigation of the L-R swap problem on the MS2109 reveals that the problem isn't that the channels are swapped, but rather that they are swapped and also out of phase by one sample. In other words, the issue is actually that the very first frame that comes from the hardware is a half-frame containing only the right channel, and after that everything becomes offset. So introduce a new quirk field to drop the very first 2 bytes that come in after the format is configured and a capture stream starts. This puts the channels in phase and in the correct order. Cc: stable@vger.kernel.org Signed-off-by: Hector Martin Link: https://lore.kernel.org/r/20200810082400.225858-1-marcan@marcan.st Signed-off-by: Takashi Iwai Signed-off-by: Greg Kroah-Hartman --- diff --git a/sound/usb/card.h b/sound/usb/card.h index 71778ca4b26aa..b24f2efea1cb4 100644 --- a/sound/usb/card.h +++ b/sound/usb/card.h @@ -125,6 +125,7 @@ struct snd_usb_substream { unsigned int tx_length_quirk:1; /* add length specifier to transfers */ 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) */ + unsigned int stream_offset_adj; /* Bytes to drop from beginning of stream (for non-compliant devices) */ unsigned int running: 1; /* running status */ diff --git a/sound/usb/pcm.c b/sound/usb/pcm.c index f84c55ecd0fb4..c97d9a537f763 100644 --- a/sound/usb/pcm.c +++ b/sound/usb/pcm.c @@ -1302,6 +1302,12 @@ static void retire_capture_urb(struct snd_usb_substream *subs, // continue; } bytes = urb->iso_frame_desc[i].actual_length; + if (subs->stream_offset_adj > 0) { + unsigned int adj = min(subs->stream_offset_adj, bytes); + cp += adj; + bytes -= adj; + subs->stream_offset_adj -= adj; + } frames = bytes / stride; if (!subs->txfr_quirk) bytes = frames * stride; diff --git a/sound/usb/quirks.c b/sound/usb/quirks.c index 47979c9c3e290..59529a9cab614 100644 --- a/sound/usb/quirks.c +++ b/sound/usb/quirks.c @@ -1122,6 +1122,9 @@ void snd_usb_set_format_quirk(struct snd_usb_substream *subs, case USB_ID(0x041e, 0x3f19): /* E-Mu 0204 USB */ set_format_emu_quirk(subs, fmt); break; + case USB_ID(0x534d, 0x2109): /* MacroSilicon MS2109 */ + subs->stream_offset_adj = 2; + break; } } diff --git a/sound/usb/stream.c b/sound/usb/stream.c index 3b23102230c03..1ffc32fd3a9eb 100644 --- a/sound/usb/stream.c +++ b/sound/usb/stream.c @@ -95,6 +95,7 @@ static void snd_usb_init_substream(struct snd_usb_stream *as, subs->tx_length_quirk = as->chip->tx_length_quirk; subs->speed = snd_usb_get_speed(subs->dev); subs->pkt_offset_adj = 0; + subs->stream_offset_adj = 0; snd_usb_set_pcm_ops(as->pcm, stream);