mixer: remove volume backwards compat, add % interpretation

The current situation is fairly confusing, where an integer is interpreted
as a percent until you slap a decimal on it and magically it becomes an
absolute value.

Let's have a flag day in 14.0 and remove this shim entirely.  Setting with
percent can still be useful, so allow a trailing '%' to indicate as such.
As a side effect, we tighten down the format allowed in the volume a little
bit by ensuring there's no trailing garbage after the value once it's
separated into left and right components.

Reviewed by:	christos, hselasky, pauamma_gundo.com (manpages)
Relnotes:	yes
Differential Revision:	https://reviews.freebsd.org/D35101

7 files changed, 42 insertions, 30 deletions

diff --git a/sbin/devd/apple.conf b/sbin/devd/apple.conf
index 0729a9c86e7a..0a9143f7b5a5 100644
--- a/sbin/devd/apple.conf
+++ b/sbin/devd/apple.conf
@@ -52,7 +52,7 @@ notify 0 {
 	match "subsystem"	"keys";
 	match "type"		"volume";
 	match "notify"		"down";
-	action			"mixer vol.volume=-10";
+	action			"mixer vol.volume=-10%";
 };
 
 notify 0 {
@@ -60,7 +60,7 @@ notify 0 {
 	match "subsystem"	"keys";
 	match "type"		"volume";
 	match "notify"		"up";
-	action			"mixer vol.volume=+10";
+	action			"mixer vol.volume=+10%";
 };
 
 # Eject key
diff --git a/sbin/devd/asus.conf b/sbin/devd/asus.conf
index eed369f6ca4d..0074e7a7c55f 100644
--- a/sbin/devd/asus.conf
+++ b/sbin/devd/asus.conf
@@ -14,14 +14,14 @@ notify 0 {
 	match "system"		"ACPI";
 	match "subsystem"	"ASUS";
 	match "notify"		"0x31";
-	action			"mixer vol.volume=-10";
+	action			"mixer vol.volume=-10%";
 };
 
 notify 0 {
 	match "system"		"ACPI";
 	match "subsystem"	"ASUS";
 	match "notify"		"0x30";
-	action			"mixer vol.volume=+10";
+	action			"mixer vol.volume=+10%";
 };
 
 # The next blocks enable volume hotkeys that can be found on the Asus EeePC
@@ -36,14 +36,14 @@ notify 0 {
         match "system"          "ACPI";
         match "subsystem"       "ASUS-Eee";
         match "notify"          "0x14";
-        action                  "mixer vol.volume=-10";
+        action                  "mixer vol.volume=-10%";
 };
 
 notify 0 {
         match "system"          "ACPI";
         match "subsystem"       "ASUS-Eee";
         match "notify"          "0x15";
-        action                  "mixer vol.volume=+10";
+        action                  "mixer vol.volume=+10%";
 };
 
 # Enable user hotkeys that can be found on the Asus EeePC
diff --git a/share/man/man4/acpi_ibm.4 b/share/man/man4/acpi_ibm.4
index 290c7d3b29c1..434a1a7cba2c 100644
--- a/share/man/man4/acpi_ibm.4
+++ b/share/man/man4/acpi_ibm.4
@@ -455,7 +455,7 @@ case ${NOTIFY} in
 		fi
 		if [ $LEVEL -eq 1 ]; then
 			sysctl dev.acpi_ibm.0.mic_led=0
-			mixer rec.volume=30
+			mixer rec.volume=30%
 		fi
 		;;
         *)
diff --git a/usr.bin/fortune/datfiles/freebsd-tips b/usr.bin/fortune/datfiles/freebsd-tips
index e8fa84e02489..930110a0c3fe 100644
--- a/usr.bin/fortune/datfiles/freebsd-tips
+++ b/usr.bin/fortune/datfiles/freebsd-tips
@@ -339,7 +339,7 @@ If you have sudo(8) installed and permissions to use it, type
 ``<ESC>w ! sudo tee %'' to force a write.
 %
 You can adjust the volume of various parts of the sound system in your
-computer by typing 'mixer <type>.volume=<volume>'.  To get a list of what
+computer by typing 'mixer <type>.volume=<volume>%'.  To get a list of what
 you can adjust, just type 'mixer'.
 %
 You can automatically download and install binary packages by doing
diff --git a/usr.bin/usbhidaction/usbhidaction.1 b/usr.bin/usbhidaction/usbhidaction.1
index f50af8fff1ad..54d114925714 100644
--- a/usr.bin/usbhidaction/usbhidaction.1
+++ b/usr.bin/usbhidaction/usbhidaction.1
@@ -139,11 +139,11 @@ The following configuration file can be used to control a pair
 of Philips USB speakers with the HID controls on the speakers.
 .Bd -literal -offset indent
 # Configuration for various Philips USB speakers
-Consumer:Volume_Increment		 1 0 mixer -f $1 vol.volume=+1
-Consumer:Volume_Decrement		 1 0 mixer -f $1 vol.volume=-1
+Consumer:Volume_Increment		 1 0 mixer -f $1 vol.volume=+1%
+Consumer:Volume_Decrement		 1 0 mixer -f $1 vol.volume=-1%
 Consumer:Mute				 1 0 mixer -f $1 vol.mute=^
-Consumer:Channel_Top.Microsoft:Base_Up	 1 0 mixer -f $1 bass.volume=+1
-Consumer:Channel_Top.Microsoft:Base_Down 1 0 mixer -f $1 bass.volume=-1
+Consumer:Channel_Top.Microsoft:Base_Up	 1 0 mixer -f $1 bass.volume=+1%
+Consumer:Channel_Top.Microsoft:Base_Down 1 0 mixer -f $1 bass.volume=-1%
 .Ed
 .Pp
 A sample invocation using this configuration would be
@@ -153,9 +153,9 @@ A sample invocation using this configuration would be
 The following example controls the mixer volume using a Logitech Wingman.
 Notice the debounce of 1 for buttons and 5 for the slider.
 .Bd -literal -offset indent
-Button:Button_1	  1 1	mixer vol.volume=+10
-Button:Button_2	  1 1	mixer vol.volume=-10
-Generic_Desktop:Z * 5	mixer vol.volume=`echo $V | awk '{print int($$1/255*100)}'`
+Button:Button_1	  1 1	mixer vol.volume=+10%
+Button:Button_2	  1 1	mixer vol.volume=-10%
+Generic_Desktop:Z * 5	mixer vol.volume=`echo $V | awk '{printf("%.02f", $$1/255)}'`
 .Ed
 .Sh SEE ALSO
 .Xr usbhidctl 1 ,
diff --git a/usr.sbin/mixer/mixer.8 b/usr.sbin/mixer/mixer.8
index 284750538f7e..9a76cbe41f65 100644
--- a/usr.sbin/mixer/mixer.8
+++ b/usr.sbin/mixer/mixer.8
@@ -21,7 +21,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd March 20, 2022
+.Dd April 29, 2022
 .Dt MIXER 8
 .Os
 .Sh NAME
@@ -112,8 +112,8 @@ with one of the available devices):
 .It Sy Name Ta Sy Value
 .It Ar dev Cm .volume Ta Xo
 .Ar vol |
-.Oo Cm \&+ | Cm \&- Oc Ar lvol
-.Oo Cm \&: Oo Cm \&+ | Cm \&- Oc Ar rvol Oc
+.Oo Cm \&+ | Cm \&- Oc Ar lvol Oo % Oc
+.Oo Cm \&: Oo Cm \&+ | Cm \&- Oc Ar rvol Oo % Oc Oc
 .Xc
 .It Ar dev Cm .mute Ta Cm 0 | 1 | ^
 .It Ar dev Cm .recsrc Ta Cm ^ | + | - | =
@@ -128,16 +128,21 @@ The optional
 and/or
 .Ar rvol
 values have to be specified.
-The values have to be normalized 32-bit floats, from 0.0 to 1.0 inclusively.
-If no
-.Ql \&.
-character is present, the value is treated like a percentage, for backwards compatibility.
+The values should typically be decimal numbers between 0 and 1 with at most 2
+digits after the decimal point.
+A trailing percent sign indicates that the value should be treated as a
+percentage of 1.0, rather than an absolute value.
+Thus, 70% means the same as 0.7.
 If the left or right volume values are prefixed with
 .Cm +
 or
 .Cm - ,
 the value following will be used as a relative adjustment, modifying the
 current settings by the amount specified.
+Note that relative percentages are still relative to 1.0, not to the current
+value.
+If the volume is currently 0.40 and an adjustment of +20% is specified, then
+thet final volume will be set to 0.60.
 .Pp
 Volume can also be set using the shorthand
 .Ar dev Ns Cm =value .
diff --git a/usr.sbin/mixer/mixer.c b/usr.sbin/mixer/mixer.c
index c0a9ec25c6fa..e216efe3313c 100644
--- a/usr.sbin/mixer/mixer.c
+++ b/usr.sbin/mixer/mixer.c
@@ -341,7 +341,7 @@ mod_volume(struct mix_dev *d, void *p)
 	mix_ctl_t *cp;
 	mix_volume_t v;
 	const char *val;
-	char lstr[8], rstr[8];
+	char *endp, lstr[8], rstr[8];
 	float lprev, rprev, lrel, rrel;
 	int n;
 
@@ -356,25 +356,32 @@ mod_volume(struct mix_dev *d, void *p)
 	lrel = rrel = 0;
 	if (n > 0) {
 		if (*lstr == '+' || *lstr == '-')
-			lrel = rrel = 1;
-		v.left = strtof(lstr, NULL);
+			lrel = 1;
+		v.left = strtof(lstr, &endp);
+		if (*endp != '\0' && (*endp != '%' || *(endp + 1) != '\0')) {
+			warnx("invalid volume value: %s", lstr);
+			return (-1);
+		}
 
-		/* be backwards compatible */
-		if (strstr(lstr, ".") == NULL)
+		if (*endp == '%')
 			v.left /= 100.0f;
 	}
 	if (n > 1) {
 		if (*rstr == '+' || *rstr == '-')
 			rrel = 1;
-		v.right = strtof(rstr, NULL);
+		v.right = strtof(rstr, &endp);
+		if (*endp != '\0' && (*endp != '%' || *(endp + 1) != '\0')) {
+			warnx("invalid volume value: %s", rstr);
+			return (-1);
+		}
 
-		/* be backwards compatible */
-		if (strstr(rstr, ".") == NULL)
+		if (*endp == '%')
 			v.right /= 100.0f;
 	}
 	switch (n) {
 	case 1:
 		v.right = v.left; /* FALLTHROUGH */
+		rrel = lrel;
 	case 2:
 		if (lrel)
 			v.left += m->dev->vol.left;