ALSA: hda: Fix headset detection failure due to unstable sort

The auto_parser assumed sort() was stable, but the kernel's sort() uses
heapsort, which has never been stable. After commit 0e02ca29a563
("lib/sort: optimize heapsort with double-pop variation"), the order of
equal elements changed, causing the headset to fail to work.

Fix the issue by recording the original order of elements before
sorting and using it as a tiebreaker for equal elements in the
comparison function.

Fixes: b9030a005d58 ("ALSA: hda - Use standard sort function in hda_auto_parser.c")
Reported-by: Austrum <austrum.lab@gmail.com>
Closes: https://bugzilla.kernel.org/show_bug.cgi?id=219158
Tested-by: Austrum <austrum.lab@gmail.com>
Cc: stable@vger.kernel.org
Signed-off-by: Kuan-Wei Chiu <visitorckw@gmail.com>
Link: https://patch.msgid.link/20250128165415.643223-1-visitorckw@gmail.com
Signed-off-by: Takashi Iwai <tiwai@suse.de>

diff --git a/sound/pci/hda/hda_auto_parser.c b/sound/pci/hda/hda_auto_parser.c
index 84393f4f429dff9e26e04d0e69f52c457dd04345..8923813ce4247d579e60ca30a7f3fb10995b4d59 100644 (file)
--- a/sound/pci/hda/hda_auto_parser.c
+++ b/sound/pci/hda/hda_auto_parser.c
@@ -80,7 +80,11 @@ static int compare_input_type(const void *ap, const void *bp)
 
        /* In case one has boost and the other one has not,
           pick the one with boost first. */
-       return (int)(b->has_boost_on_pin - a->has_boost_on_pin);
+       if (a->has_boost_on_pin != b->has_boost_on_pin)
+               return (int)(b->has_boost_on_pin - a->has_boost_on_pin);
+
+       /* Keep the original order */
+       return a->order - b->order;
 }
 
 /* Reorder the surround channels
@@ -400,6 +404,8 @@ int snd_hda_parse_pin_defcfg(struct hda_codec *codec,
        reorder_outputs(cfg->speaker_outs, cfg->speaker_pins);
 
        /* sort inputs in the order of AUTO_PIN_* type */
+       for (i = 0; i < cfg->num_inputs; i++)
+               cfg->inputs[i].order = i;
        sort(cfg->inputs, cfg->num_inputs, sizeof(cfg->inputs[0]),
             compare_input_type, NULL);
 

diff --git a/sound/pci/hda/hda_auto_parser.h b/sound/pci/hda/hda_auto_parser.h
index 579b11beac718e4847c2a186ee733ee985066158..87af3d8c02f7f68ffa7c9006fdcf43d836e939eb 100644 (file)
--- a/sound/pci/hda/hda_auto_parser.h
+++ b/sound/pci/hda/hda_auto_parser.h
@@ -37,6 +37,7 @@ struct auto_pin_cfg_item {
        unsigned int is_headset_mic:1;
        unsigned int is_headphone_mic:1; /* Mic-only in headphone jack */
        unsigned int has_boost_on_pin:1;
+       int order;
 };
 
 struct auto_pin_cfg;