Changeset 55388 in vbox for trunk/src/VBox/Devices/Audio/DevIchHdaCodec.cpp

Timestamp:

Apr 22, 2015 4:55:56 PM (10 years ago)

Author:

vboxsync

Message:

HDA: Volume handling improvements.

File:

• trunk/src/VBox/Devices/Audio/DevIchHdaCodec.cpp (modified) (1 diff)

trunk/src/VBox/Devices/Audio/DevIchHdaCodec.cpp

@@ -1204 +1204 @@
     uint8_t rVol = AMPLIFIER_REGISTER(*pAmp, dir, AMPLIFIER_RIGHT, 0) & 0x7f;
 
+    /* The STAC9220 volume controls have 0 to -96dB attenuation range in 128 steps.
+     * We have 0 to -48dB range in 256 steps. HDA volume setting of 127 must map
+     * to 255 internally (0dB), while HDA volume setting of 63 (-48dB) and below
+     * should map  to 1 (rather than zero) internally.
+     */
+    if (lVol > 63)
+        lVol = (lVol - 63) * (4 * 255) / 256;
+    else
+        lVol = 1;   /* Not quite zero. */
+
+    if (rVol > 63)
+        rVol = (rVol - 63) * (4 * 255) / 256;
+    else
+        rVol = 1;   /* Not quite zero. */
+
 #ifdef VBOX_WITH_PDM_AUDIO_DRIVER
     /** @todo In SetVolume no passing audmixerctl_in as its not used in DrvAudio.cpp. */