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: v5.7.16~57 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=0bf5808a668943e9e7d1d2838c998ed30def29c0;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 f39f23e3525df..d8ec5caf464de 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 0247162a9fbf3..9538684c9b4e0 100644 --- a/sound/usb/pcm.c +++ b/sound/usb/pcm.c @@ -1416,6 +1416,12 @@ 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 d7d900ebcf37f..497a7249f2584 100644 --- a/sound/usb/quirks.c +++ b/sound/usb/quirks.c @@ -1468,6 +1468,9 @@ 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 15296f2c902cd..e03ff2a7a73fb 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);