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>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.