From ff114bcd7635211d051c6031fac800fd45424ece 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 ed87cc83eb47d..0cde519bfa420 100644 --- a/sound/usb/card.h +++ b/sound/usb/card.h @@ -126,6 +126,7 @@ 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 ff38fca1781b6..f27213b846e6b 100644 --- a/sound/usb/pcm.c +++ b/sound/usb/pcm.c @@ -1313,6 +1313,12 @@ 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 cd36394e27ae6..4f4dc43e56a7b 100644 --- a/sound/usb/quirks.c +++ b/sound/usb/quirks.c @@ -1120,6 +1120,9 @@ 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 d1776e5517ffe..452646959586e 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); -- 2.51.0