ALSA: via82xx: allow changing the initial DXS volume

As per-stream volume controls, the DXS controls are not intended to
adjust the overall sound level and so are initialized every time
a stream is opened.  However, there are special situations where one
wants to reduce the overall volume in the digital domain, i.e., before
the AC'97 codec's PCM volume control.  To allow this, add a module
parameter that sets the initial DXS volume.

Signed-off-by: Clemens Ladisch <clemens@ladisch.de>
Tested-by: Soeren D. Schulze <soeren.d.schulze@gmx.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

diff --git a/sound/pci/via82xx.c b/sound/pci/via82xx.c
index 7e494b6a1d0e4b63ce6171dbe82d3efa75ce024e..8c5f8b5a59f0d82aa0a734eb6e37bf800cc6ef06 100644 (file)
--- a/sound/pci/via82xx.c
+++ b/sound/pci/via82xx.c
@@ -85,6 +85,7 @@ static int joystick;
 static int ac97_clock = 48000;
 static char *ac97_quirk;
 static int dxs_support;
+static int dxs_init_volume = 31;
 static int nodelay;
 
 module_param(index, int, 0444);
@@ -103,6 +104,8 @@ module_param(ac97_quirk, charp, 0444);
 MODULE_PARM_DESC(ac97_quirk, "AC'97 workaround for strange hardware.");
 module_param(dxs_support, int, 0444);
 MODULE_PARM_DESC(dxs_support, "Support for DXS channels (0 = auto, 1 = enable, 2 = disable, 3 = 48k only, 4 = no VRA, 5 = enable any sample rate)");
+module_param(dxs_init_volume, int, 0644);
+MODULE_PARM_DESC(dxs_init_volume, "initial DXS volume (0-31)");
 module_param(nodelay, int, 0444);
 MODULE_PARM_DESC(nodelay, "Disable 500ms init delay");
 
@@ -1245,8 +1248,10 @@ static int snd_via8233_playback_open(struct snd_pcm_substream *substream)
                return err;
        stream = viadev->reg_offset / 0x10;
        if (chip->dxs_controls[stream]) {
-               chip->playback_volume[stream][0] = 0;
-               chip->playback_volume[stream][1] = 0;
+               chip->playback_volume[stream][0] =
+                               VIA_DXS_MAX_VOLUME - (dxs_init_volume & 31);
+               chip->playback_volume[stream][1] =
+                               VIA_DXS_MAX_VOLUME - (dxs_init_volume & 31);
                chip->dxs_controls[stream]->vd[0].access &=
                        ~SNDRV_CTL_ELEM_ACCESS_INACTIVE;
                snd_ctl_notify(chip->card, SNDRV_CTL_EVENT_MASK_VALUE |