On Sun, 13 Dec 2015 19:49:58 +0100, Anssi Hannula wrote:
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
Applied, thanks.
Takashi
It took a bit longer than expected for me to get back to this, but here goes :)
sound/usb/mixer.c | 2 ++ sound/usb/mixer_maps.c | 12 ------------ sound/usb/mixer_quirks.c | 37 +++++++++++++++++++++++++++++++++++++ sound/usb/mixer_quirks.h | 4 ++++ 4 files changed, 43 insertions(+), 12 deletions(-)
diff --git a/sound/usb/mixer.c b/sound/usb/mixer.c index f494dced3c11..4f85757009b3 100644 --- a/sound/usb/mixer.c +++ b/sound/usb/mixer.c @@ -1354,6 +1354,8 @@ static void build_feature_ctl(struct mixer_build *state, void *raw_desc, } }
- snd_usb_mixer_fu_apply_quirk(state->mixer, cval, unitid, kctl);
- range = (cval->max - cval->min) / cval->res; /*
- Are there devices with volume range more than 255? I use a bit more
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 */
};
diff --git a/sound/usb/mixer_quirks.c b/sound/usb/mixer_quirks.c index fe91184ce832..0ce888dceed0 100644 --- a/sound/usb/mixer_quirks.c +++ b/sound/usb/mixer_quirks.c @@ -37,6 +37,7 @@ #include <sound/control.h> #include <sound/hwdep.h> #include <sound/info.h> +#include <sound/tlv.h>
#include "usbaudio.h" #include "mixer.h" @@ -1825,3 +1826,39 @@ void snd_usb_mixer_rc_memory_change(struct usb_mixer_interface *mixer, } }
+static void snd_dragonfly_quirk_db_scale(struct usb_mixer_interface *mixer,
struct snd_kcontrol *kctl)+{
- /* Approximation using 10 ranges based on output measurement on hw v1.2.
* This seems close to the cubic mapping e.g. alsamixer uses. */- static const DECLARE_TLV_DB_RANGE(scale,
0, 1, TLV_DB_MINMAX_ITEM(-5300, -4970),2, 5, TLV_DB_MINMAX_ITEM(-4710, -4160),6, 7, TLV_DB_MINMAX_ITEM(-3884, -3710),8, 14, TLV_DB_MINMAX_ITEM(-3443, -2560),15, 16, TLV_DB_MINMAX_ITEM(-2475, -2324),17, 19, TLV_DB_MINMAX_ITEM(-2228, -2031),20, 26, TLV_DB_MINMAX_ITEM(-1910, -1393),27, 31, TLV_DB_MINMAX_ITEM(-1322, -1032),32, 40, TLV_DB_MINMAX_ITEM(-968, -490),41, 50, TLV_DB_MINMAX_ITEM(-441, 0),- );
- usb_audio_info(mixer->chip, "applying DragonFly dB scale quirk\n");
- kctl->tlv.p = scale;
- kctl->vd[0].access |= SNDRV_CTL_ELEM_ACCESS_TLV_READ;
- kctl->vd[0].access &= ~SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK;
+}
+void snd_usb_mixer_fu_apply_quirk(struct usb_mixer_interface *mixer,
struct usb_mixer_elem_info *cval, int unitid,struct snd_kcontrol *kctl)+{
- switch (mixer->chip->usb_id) {
- case USB_ID(0x21b4, 0x0081): /* AudioQuest DragonFly */
if (unitid == 7 && cval->min == 0 && cval->max == 50)snd_dragonfly_quirk_db_scale(mixer, kctl);break;- }
+}
diff --git a/sound/usb/mixer_quirks.h b/sound/usb/mixer_quirks.h index bdbfab093816..177c329cd4dd 100644 --- a/sound/usb/mixer_quirks.h +++ b/sound/usb/mixer_quirks.h @@ -9,5 +9,9 @@ void snd_emuusb_set_samplerate(struct snd_usb_audio *chip, void snd_usb_mixer_rc_memory_change(struct usb_mixer_interface *mixer, int unitid);
+void snd_usb_mixer_fu_apply_quirk(struct usb_mixer_interface *mixer,
struct usb_mixer_elem_info *cval, int unitid,struct snd_kcontrol *kctl);#endif /* SND_USB_MIXER_QUIRKS_H */
-- 2.3.10