[PATCH] ALSA: fm801: Fix probe error

[Ioannis Barkas <jnyb.de@gmail.com>]

Trying to use my FM801 card resulted in no sound card listed at OS
Driver probe fails, and no card is registered on my old test PC:

snd_fm801 0000:08:08.0:
 control 2:0:0:IEC958 Capture Switch:0 is already present
snd_fm801 0000:08:08.0:
 probe with driver snd_fm801 failed with error -16

snd_fm801 0000:08:08.0:
 control 2:0:0:IEC958 Playback Switch:0 is already present
snd_fm801 0000:08:08.0:
 probe with driver snd_fm801 failed with error -16

Identical controls already registered by AC97 layer when the
codec reports S/PDIF support:

  "IEC958 Capture Switch"  - added by the ALC650 family patch
                             (snd_ac97_spdif_controls_alc655)
  "IEC958 Playback Switch" - added by the AC97 core
                             (snd_ac97_controls_spdif)

FM801 controls drive different registers (FM801_I2S_MODE bit 8
and FM801_GEN_CTRL bit 2) from the codec ones. Give FM801 controls
distinct names to avoid duplicates:
  "IEC958 Capture Switch"  -> "IEC958 I2S Capture Switch"
  "IEC958 Playback Switch" -> "IEC958 FM801 Playback Switch"

Patch restores full audio functionality within OS

Investigation and patch development assisted by Claude (Anthropic AI)

Signed-off-by: Ioannis Barkas jnyb.de@gmail.com
---
 sound/pci/fm801.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/sound/pci/fm801.c b/sound/pci/fm801.c
index 9cc96b807d..96fabb0c56 100644
--- a/sound/pci/fm801.c
+++ b/sound/pci/fm801.c
@@ -1018,10 +1018,10 @@ FM801_SINGLE("FM Playback Switch", FM801_FM_VOL, 15, 1, 1),
 static const struct snd_kcontrol_new snd_fm801_controls_multi[] = {
 FM801_SINGLE("AC97 2ch->4ch Copy Switch", FM801_CODEC_CTRL, 7, 1, 0),
 FM801_SINGLE("AC97 18-bit Switch", FM801_CODEC_CTRL, 10, 1, 0),
-FM801_SINGLE(SNDRV_CTL_NAME_IEC958("",CAPTURE,SWITCH), FM801_I2S_MODE, 8, 1, 0),
+FM801_SINGLE(SNDRV_CTL_NAME_IEC958("I2S ",CAPTURE,SWITCH), FM801_I2S_MODE, 8, 1, 0),
 FM801_SINGLE(SNDRV_CTL_NAME_IEC958("Raw Data ",PLAYBACK,SWITCH), FM801_I2S_MODE, 9, 1, 0),
 FM801_SINGLE(SNDRV_CTL_NAME_IEC958("Raw Data ",CAPTURE,SWITCH), FM801_I2S_MODE, 10, 1, 0),
-FM801_SINGLE(SNDRV_CTL_NAME_IEC958("",PLAYBACK,SWITCH), FM801_GEN_CTRL, 2, 1, 0),
+FM801_SINGLE(SNDRV_CTL_NAME_IEC958("FM801 ",PLAYBACK,SWITCH), FM801_GEN_CTRL, 2, 1, 0),
 };
 
 static int snd_fm801_mixer(struct fm801 *chip)
-- 
2.53.0