[RFC PATCH 09/11] ALSA: mixer_audient: Add readback-free parameter set

[Christian Ruppert <arc@gmx.li>]

Add a flag to systematically force parameter writing without prior readback
to certain control types. In preparation of the id14 driver.

Signed-off-by: Christian Ruppert <arc@gmx.li>
---
 sound/usb/mixer_audient.c | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/sound/usb/mixer_audient.c b/sound/usb/mixer_audient.c
index 803487ced997..7cb8245a64d0 100644
--- a/sound/usb/mixer_audient.c
+++ b/sound/usb/mixer_audient.c
@@ -37,6 +37,7 @@ static const DECLARE_TLV_DB_MINMAX_MUTE(snd_audient_tlv_mixer, -12800, 600);
 
 #define SND_AUDIENT_CTYPE_FLAGS_SIGNED		(1L <<  0)
 #define SND_AUDIENT_CTYPE_FLAGS_INIT_HW		(1L <<  1)
+#define SND_AUDIENT_CTYPE_FLAGS_FORCE_SET	(1L <<  2)
 
 static const struct snd_audient_ctrl_type {
 	snd_ctl_elem_type_t type;
@@ -313,9 +314,13 @@ static int snd_audient_raw_set_one(struct usb_mixer_interface *const mixer,
 	int ret;
 	u32 buf;
 
-	ret = snd_audient_raw_get_one(mixer, ctype, cidx, &buf);
-	if (ret < 0)
-		return ret;
+	if (ctype->flags & SND_AUDIENT_CTYPE_FLAGS_FORCE_SET) {
+		buf = !value;		/* just make it different */
+	} else {
+		ret = snd_audient_raw_get_one(mixer, ctype, cidx, &buf);
+		if (ret < 0)
+			return ret;
+	}
 
 	if (buf != value) {
 		buf = cpu_to_le32(value);
-- 
2.56.0