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authorHenrique de Moraes Holschuh <hmh@hmh.eng.br>2009-12-16 02:51:10 +0300
committerLen Brown <len.brown@intel.com>2009-12-16 07:57:35 +0300
commitc7ac6291ea7ebc568a1fce16fed87d102898f264 (patch)
treebb227ae67f0bad13b9935f03ed7ec65e04470ddd /drivers/platform
parenta112ceee673629afc204bf6b4a4828a6143a083f (diff)
downloadlinux-c7ac6291ea7ebc568a1fce16fed87d102898f264.tar.xz
thinkpad-acpi: disable volume control
Disable volume control by default. It can be enabled at module load time by a module parameter (volume_control=1). The audio control mixer that thinkpad-acpi interacts with is fully functional without any drivers, and operated by hotkeys. The idea behind the console audio control is that the human operator is the only one that can interact with it. The ThinkVantage suite in Windows does not allow any software-based overrides, and only does OSD (on-screen-display) functions. The Linux driver will, with the addition of the ALSA interface, try to follow and enforce the ThinkVantage UI design: The user is supposed to use the keyboard hotkeys to interact with the console audio control. The kernel and the desktop environment is supposed to cooperate to provide proper user feedback through on-screen-display functions. Distros are urged to not to enable volume control by default. Enabling this must be a local admin's decision. This is the reason why there is no Kconfig option. Keep in mind that all ThinkPads have a normal, main mixer (AC97 or HDA) for regular software-based audio control. We are not talking about that mixer here. Advanced users are, of course, free to enable volume control and do as they please. Signed-off-by: Henrique de Moraes Holschuh <hmh@hmh.eng.br> Cc: Lorne Applebaum <lorne.applebaum@gmail.com> Cc: Matthew Garrett <mjg@redhat.com> Signed-off-by: Len Brown <len.brown@intel.com>
Diffstat (limited to 'drivers/platform')
-rw-r--r--drivers/platform/x86/thinkpad_acpi.c47
1 files changed, 42 insertions, 5 deletions
diff --git a/drivers/platform/x86/thinkpad_acpi.c b/drivers/platform/x86/thinkpad_acpi.c
index 4d909d5a0340..2d74926913d2 100644
--- a/drivers/platform/x86/thinkpad_acpi.c
+++ b/drivers/platform/x86/thinkpad_acpi.c
@@ -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 " \