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authorAnssi Hannula <anssi.hannula@iki.fi>2015-12-13 21:49:58 +0300
committerTakashi Iwai <tiwai@suse.de>2015-12-14 12:13:17 +0300
commit42e3121d90f42e57f6dbd6083dff2f57b3ec7daa (patch)
tree57c53b919f92c3a88a2f815dd630a5eb18c40eb3 /sound/usb/mixer_maps.c
parent9f9499ae8e6415cefc4fe0a96ad0e27864353c89 (diff)
downloadlinux-42e3121d90f42e57f6dbd6083dff2f57b3ec7daa.tar.xz
ALSA: usb-audio: Add a more accurate volume quirk for AudioQuest DragonFly
AudioQuest DragonFly DAC reports a volume control range of 0..50 (0x0000..0x0032) which in USB Audio means a range of 0 .. 0.2dB, which is obviously incorrect and would cause software using the dB information in e.g. volume sliders to have a massive volume difference in 100..102% range. Commit 2d1cb7f658fb ("ALSA: usb-audio: add dB range mapping for some devices") added a dB range mapping for it with range 0..50 dB. However, the actual volume mapping seems to be neither linear volume nor linear dB scale, but instead quite close to the cubic mapping e.g. alsamixer uses, with a range of approx. -53...0 dB. Replace the previous quirk with a custom dB mapping based on some basic output measurements, using a 10-item range TLV (which will still fit in alsa-lib MAX_TLV_RANGE_SIZE). Tested on AudioQuest DragonFly HW v1.2. The quirk is only applied if the range is 0..50, so if this gets fixed/changed in later HW revisions it will no longer be applied. v2: incorporated Takashi Iwai's suggestion for the quirk application method Signed-off-by: Anssi Hannula <anssi.hannula@iki.fi> Cc: <stable@vger.kernel.org> Signed-off-by: Takashi Iwai <tiwai@suse.de>
Diffstat (limited to 'sound/usb/mixer_maps.c')
-rw-r--r--sound/usb/mixer_maps.c12
1 files changed, 0 insertions, 12 deletions
diff --git a/sound/usb/mixer_maps.c b/sound/usb/mixer_maps.c
index 6a803eff87f7..ddca6547399b 100644
--- a/sound/usb/mixer_maps.c
+++ b/sound/usb/mixer_maps.c
@@ -348,13 +348,6 @@ static struct usbmix_name_map bose_companion5_map[] = {
{ 0 } /* terminator */
};
-/* Dragonfly DAC 1.2, the dB conversion factor is 1 instead of 256 */
-static struct usbmix_dB_map dragonfly_1_2_dB = {0, 5000};
-static struct usbmix_name_map dragonfly_1_2_map[] = {
- { 7, NULL, .dB = &dragonfly_1_2_dB },
- { 0 } /* terminator */
-};
-
/*
* Control map entries
*/
@@ -470,11 +463,6 @@ static struct usbmix_ctl_map usbmix_ctl_maps[] = {
.id = USB_ID(0x05a7, 0x1020),
.map = bose_companion5_map,
},
- {
- /* Dragonfly DAC 1.2 */
- .id = USB_ID(0x21b4, 0x0081),
- .map = dragonfly_1_2_map,
- },
{ 0 } /* terminator */
};