This patch enables configurable support in the Realtek HD Audio driver for the ALC271 type commonly found on some Acer laptops.
It is then possible to enable such support by passing the "model=acer" parameter at boot-time. Without such parameter the driver would fall back to BIOS auto-probing and in many cases that would result in the internal microphone not working.
--- linux-2.6.38.2-original/sound/pci/hda/patch_realtek.c 2011-04-07 17:56:25.053046707 +0200 +++ linux-2.6.38.2/sound/pci/hda/patch_realtek.c 2011-04-07 19:03:00.975706888 +0200 @@ -15028,6 +15028,7 @@ static const char * const alc269_models[ [ALC269_DMIC] = "laptop-dmic", [ALC269_FUJITSU] = "fujitsu", [ALC269_LIFEBOOK] = "lifebook", + [ALC271_ACER] = "acer", [ALC269_AUTO] = "auto", };