Comment 16 for bug 1334329

https://git.kernel.org/cgit/linux/kernel/git/tiwai/sound.git/commit/sound/pci/hda?id=ab16c6dd79389761eca1366d809a002b44b7f960

 capture source control will not be created when auto mic is enabled by

adding hint

spec->line_in_auto_switch=1;

for avoiding regressions, the line-in auto switching
feature isn't activated as default. It has to be set explicitly via
spec->line_in_auto_switch flag in a fixup code.

control.8 {
  iface MIXER
  name 'Capture Source'
  value Mic
  comment {
   access 'read write'
   type ENUMERATED
   count 1
   item.0 Mic
   item.1 Line
  }
 }