@@ -1097,6 +1097,18 @@ Volume control
procfs: /proc/acpi/ibm/volume
+NOTE: by default, the volume control interface operates in read-only
+mode, as it is supposed to be used for on-screen-display purposes.
+The read/write mode can be enabled through the use of the
+"volume_control=1" module parameter.
+
+NOTE: distros are urged to not enable volume_control by default, this
+should be done by the local admin only. The ThinkPad UI is for the
+console audio control to be done through the volume keys only, and for
+the desktop environment to just provide on-screen-display feedback.
+Software volume control should be done only in the main AC97/HDA
+mixer.
+
This feature allows volume control on ThinkPad models with a digital
volume knob (when available, not all models have it), as well as
mute/unmute control. The available commands are:
@@ -1465,3 +1477,4 @@ Sysfs interface changelog:
0x020600: Marker for backlight change event support.
0x020700: Support for mute-only mixers.
+ Volume control in read-only mode by default.
@@ -311,6 +311,7 @@ static struct {
static struct {
u16 hotkey_mask_ff:1;
+ u16 volume_ctrl_forbidden:1;
} tp_warned;
struct thinkpad_id_data {
@@ -6434,6 +6435,7 @@ static enum tpacpi_volume_access_mode volume_mode =
TPACPI_VOL_MODE_MAX;
static enum tpacpi_volume_capabilities volume_capabilities;
+static int volume_control_allowed;
/*
* Used to syncronize writers to TP_EC_AUDIO and
@@ -6449,6 +6451,8 @@ static void tpacpi_volume_checkpoint_nvram(void)
if (volume_mode != TPACPI_VOL_MODE_ECNVRAM)
return;
+ if (!volume_control_allowed)
+ return;
vdbg_printk(TPACPI_DBG_MIXER,
"trying to checkpoint mixer state to NVRAM...\n");
@@ -6691,6 +6695,12 @@ static int __init volume_init(struct ibm_init_struct *iibm)
"mute is supported, volume control is %s\n",
str_supported(!tp_features.mixer_no_level_control));
+ printk(TPACPI_INFO
+ "Console audio control enabled, mode: %s\n",
+ (volume_control_allowed) ?
+ "override (read/write)" :
+ "monitor (read only)");
+
return 0;
}
@@ -6711,11 +6721,16 @@ static int volume_read(char *p)
len += sprintf(p + len, "mute:\t\t%s\n",
onoff(status, TP_EC_AUDIO_MUTESW));
- len += sprintf(p + len, "commands:\tunmute, mute\n");
- if (!tp_features.mixer_no_level_control) {
- len += sprintf(p + len, "commands:\tup, down\n");
- len += sprintf(p + len, "commands:\tlevel <level>"
- " (<level> is 0-%d)\n", TP_EC_VOLUME_MAX);
+ if (volume_control_allowed) {
+ len += sprintf(p + len, "commands:\tunmute, mute\n");
+ if (!tp_features.mixer_no_level_control) {
+ len += sprintf(p + len,
+ "commands:\tup, down\n");
+ len += sprintf(p + len,
+ "commands:\tlevel <level>"
+ " (<level> is 0-%d)\n",
+ TP_EC_VOLUME_MAX);
+ }
}
}
@@ -6730,6 +6745,23 @@ static int volume_write(char *buf)
char *cmd;
int rc;
+ /*
+ * We do allow volume control at driver startup, so that the
+ * user can set initial state through the volume=... parameter hack.
+ */
+ if (!volume_control_allowed && tpacpi_lifecycle != TPACPI_LIFE_INIT) {
+ if (unlikely(!tp_warned.volume_ctrl_forbidden)) {
+ tp_warned.volume_ctrl_forbidden = 1;
+ printk(TPACPI_NOTICE
+ "Console audio control in monitor mode, "
+ "changes are not allowed.\n");
+ printk(TPACPI_NOTICE
+ "Use the volume_control=1 module parameter "
+ "to enable volume control\n");
+ }
+ return -EPERM;
+ }
+
rc = volume_get_status(&s);
if (rc < 0)
return rc;
@@ -8515,6 +8547,11 @@ MODULE_PARM_DESC(volume_capabilities,
"Selects the mixer capabilites: "
"0=auto, 1=volume and mute, 2=mute only");
+module_param_named(volume_control, volume_control_allowed, bool, 0444);
+MODULE_PARM_DESC(volume_control,
+ "Enables software override for the console audio "
+ "control when true");
+
#define TPACPI_PARAM(feature) \
module_param_call(feature, set_ibm_param, NULL, NULL, 0); \
MODULE_PARM_DESC(feature, "Simulates thinkpad-acpi procfs command " \