ALSA: hda: Fix 0 dB offset for HP laptops using CX20551 (Waikiki)

BugLink: https://launchpad.net/bugs/420578
The OR has verified that his hardware distorts because of the 0 dB
offset not corresponding to the highest PCM level. Fix this by capping
said PCM level to 0 dB similarly to what we do for CX20549 (Venice).

Reported-by: Mike Pontillo <pontillo@gmail.com>
Tested-by: Mike Pontillo <pontillo@gmail.com>
Cc: <stable@kernel.org>
Signed-off-by: Daniel T Chen <crimsun@ubuntu.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

diff --git a/sound/pci/hda/patch_conexant.c b/sound/pci/hda/patch_conexant.c
index 194a28c5499219b99d3b10ed2ae357cde7707679..61682e1d09da9388048b3a1d95fce96a44001175 100644 (file)
--- a/sound/pci/hda/patch_conexant.c
+++ b/sound/pci/hda/patch_conexant.c
@@ -1591,6 +1591,21 @@ static int patch_cxt5047(struct hda_codec *codec)
 #endif 
        }
        spec->vmaster_nid = 0x13;
+
+       switch (codec->subsystem_id >> 16) {
+       case 0x103c:
+               /* HP laptops have really bad sound over 0 dB on NID 0x10.
+                * Fix max PCM level to 0 dB (originally it has 0x1e steps
+                * with 0 dB offset 0x17)
+                */
+               snd_hda_override_amp_caps(codec, 0x10, HDA_INPUT,
+                                         (0x17 << AC_AMPCAP_OFFSET_SHIFT) |
+                                         (0x17 << AC_AMPCAP_NUM_STEPS_SHIFT) |
+                                         (0x05 << AC_AMPCAP_STEP_SIZE_SHIFT) |
+                                         (1 << AC_AMPCAP_MUTE_SHIFT));
+               break;
+       }
+
        return 0;
 }