[PATCH 5.4 16/22] ALSA: ctxfi: cthw20k2: fix mask on conf to allow 4 bits

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

From: Colin Ian King <colin.king@canonical.com>

[ Upstream commit 26a9630c72ebac7c564db305a6aee54a8edde70e ]

Currently the mask operation on variable conf is just 3 bits so
the switch statement case value of 8 is unreachable dead code.
The function daio_mgr_dao_init can be passed a 4 bit value,
function dao_rsc_init calls it with conf set to:

     conf = (desc->msr & 0x7) | (desc->passthru << 3);

so clearly when desc->passthru is set to 1 then conf can be
at least 8.

Fix this by changing the mask to 0xf.

Fixes: 8cc72361481f ("ALSA: SB X-Fi driver merge")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Link: https://lore.kernel.org/r/20210227001527.1077484-1-colin.king@canonical.com
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 sound/pci/ctxfi/cthw20k2.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/sound/pci/ctxfi/cthw20k2.c b/sound/pci/ctxfi/cthw20k2.c
index 3cd4b7dad945..b1cc4cdc6c41 100644
--- a/sound/pci/ctxfi/cthw20k2.c
+++ b/sound/pci/ctxfi/cthw20k2.c
@@ -991,7 +991,7 @@ static int daio_mgr_dao_init(void *blk, unsigned int idx, unsigned int conf)
 
 	if (idx < 4) {
 		/* S/PDIF output */
-		switch ((conf & 0x7)) {
+		switch ((conf & 0xf)) {
 		case 1:
 			set_field(&ctl->txctl[idx], ATXCTL_NUC, 0);
 			break;
-- 
2.30.1