From 10de419977bfbe9f99d1c8a3cef7cbf4660d7d84 Mon Sep 17 00:00:00 2001 From: Hector Martin Date: Mon, 10 Aug 2020 17:24:00 +0900 Subject: [PATCH] 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 --- sound/usb/card.h | 1 + sound/usb/pcm.c | 6 ++++++ sound/usb/quirks.c | 3 +++ sound/usb/stream.c | 1 + 4 files changed, 11 insertions(+) diff --git a/sound/usb/card.h b/sound/usb/card.h index f39f23e3525d..d8ec5caf464d 100644 --- a/sound/usb/card.h +++ b/sound/usb/card.h @@ -133,6 +133,7 @@ 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 d11d00efc574..7b41f9748978 100644 --- a/sound/usb/pcm.c +++ b/sound/usb/pcm.c @@ -1417,6 +1417,12 @@ 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 a8bb953cc468..a756f50d9f07 100644 --- a/sound/usb/quirks.c +++ b/sound/usb/quirks.c @@ -1432,6 +1432,9 @@ 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 11785f9652ad..d01edd5da6cf 100644 --- a/sound/usb/stream.c +++ b/sound/usb/stream.c @@ -94,6 +94,7 @@ 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);