diff options
| -rw-r--r-- | Documentation/laptops/thinkpad-acpi.txt | 13 | ||||
| -rw-r--r-- | drivers/platform/x86/thinkpad_acpi.c | 47 |
2 files changed, 55 insertions, 5 deletions
diff --git a/Documentation/laptops/thinkpad-acpi.txt b/Documentation/laptops/thinkpad-acpi.txt index bd87682103c..6a5814330e5 100644 --- a/Documentation/laptops/thinkpad-acpi.txt +++ b/Documentation/laptops/thinkpad-acpi.txt @@ -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. diff --git a/drivers/platform/x86/thinkpad_acpi.c b/drivers/platform/x86/thinkpad_acpi.c index 4d909d5a034..2d74926913d 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 " \ |