From b26a7a80e6bbf8dd17dacb127d12435d79375cf2 Mon Sep 17 00:00:00 2001 From: Roman Prucha Date: Thu, 3 Sep 2026 23:14:44 +0200 Subject: [PATCH] ALSA: ctxfi: Fix CA20K2 S/PDIF passthrough dao_rsc_init() encodes the DAIO configuration as conf = (desc->msr & 0x7) | (desc->passthru << 3); S/PDIF passthrough uses msr=1 and passthru=1, resulting in conf=9. daio_mgr_dao_init() masks conf with 0xf, but handles only values 1, 2, 4 and 8 when programming ATXCTL_NUC. As a result, conf=9 falls through to the default case and leaves NUC at its previous setting. On a Creative X-Fi Titanium HD SB1270 (CA20K2), this breaks AC3 IEC61937 passthrough when snd_ctxfi runs with reference_rate=48000,multiple=2. The receiver detects a non-audio stream but cannot decode the AC3 payload. With the unmodified driver, multiple=1 makes the same stream work. Handle conf=9 through the same NUC=0 path as conf=1. The change was runtime tested on the SB1270 with multiple=2 using IEC958 stereo PCM, pre-encoded AC3 IEC61937 passthrough and ALSA A52 live 5.1 encoding. Fixes: 26a9630c72eb ("ALSA: ctxfi: cthw20k2: fix mask on conf to allow 4 bits") Cc: stable@vger.kernel.org Assisted-by: LLM Signed-off-by: Roman Prucha Link: https://patch.msgid.link/20260903-ctxfi-spdif-conf9-fix-v1-1-5e4e3e1f801c@gmail.com Signed-off-by: Takashi Iwai --- sound/pci/ctxfi/cthw20k2.c | 1 + 1 file changed, 1 insertion(+) diff --git a/sound/pci/ctxfi/cthw20k2.c b/sound/pci/ctxfi/cthw20k2.c index 07e1490a6d17..36066ffe8784 100644 --- a/sound/pci/ctxfi/cthw20k2.c +++ b/sound/pci/ctxfi/cthw20k2.c @@ -994,6 +994,7 @@ static int daio_mgr_dao_init(struct hw *hw, void *blk, unsigned int idx, unsigne /* S/PDIF output */ switch ((conf & 0xf)) { case 1: + case 9: set_field(&ctl->txctl[idx], ATXCTL_NUC, 0); break; case 2: