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70b20dd7f8
Commitc647f806b8("ALSA: hda - Allow multiple ADCs for mic mute LED controls") changed the return value of the snd_hda_gen_add_micmute_led() without actually updating the callers. Admittedly, almost no callers actually cared about the return value. But one call site very much did: the Dell wmi code. It would see the registration return zero, which _used_ to mean "failed" but now means "success", and clear the dell_micmute_led_set_func pointer. End result: the successful registration would end up calling the Dell code that thought it had all failed, and call through a NULL pointer. To make matters worse, it ends up being a tail-call, and with the retpoline sequence you don't even see the caller (dell_micmute_update()) in the stack trace, so the error ended up way less obvious than it should have been. Fixes:c647f806b8"ALSA: hda - Allow multiple ADCs for mic mute LED controls" Cc: Takashi Iwai <tiwai@suse.de> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
49 lines
1.3 KiB
C
49 lines
1.3 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/* Helper functions for Dell Mic Mute LED control;
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* to be included from codec driver
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*/
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#if IS_ENABLED(CONFIG_DELL_LAPTOP)
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#include <linux/dell-led.h>
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static int (*dell_micmute_led_set_func)(int);
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static void dell_micmute_update(struct hda_codec *codec)
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{
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struct hda_gen_spec *spec = codec->spec;
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dell_micmute_led_set_func(spec->micmute_led.led_value);
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}
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static void alc_fixup_dell_wmi(struct hda_codec *codec,
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const struct hda_fixup *fix, int action)
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{
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bool removefunc = false;
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if (action == HDA_FIXUP_ACT_PROBE) {
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if (!dell_micmute_led_set_func)
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dell_micmute_led_set_func = symbol_request(dell_micmute_led_set);
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if (!dell_micmute_led_set_func) {
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codec_warn(codec, "Failed to find dell wmi symbol dell_micmute_led_set\n");
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return;
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}
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removefunc = (dell_micmute_led_set_func(false) < 0) ||
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(snd_hda_gen_add_micmute_led(codec,
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dell_micmute_update) < 0);
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}
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if (dell_micmute_led_set_func && (action == HDA_FIXUP_ACT_FREE || removefunc)) {
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symbol_put(dell_micmute_led_set);
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dell_micmute_led_set_func = NULL;
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}
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}
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#else /* CONFIG_DELL_LAPTOP */
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static void alc_fixup_dell_wmi(struct hda_codec *codec,
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const struct hda_fixup *fix, int action)
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{
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}
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#endif /* CONFIG_DELL_LAPTOP */
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