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ACPI: thinkpad-acpi: Remove firmware backlight delays for Intel ACPI IGD OpRegion

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Based on analysis and a patch from Matthew Garrett <mjg59@srcf.ucam.org>.

Instruct the ThinkPad ACPI firmware to remove delays on the processing of
backlight brightness changes.  This method is present on ThinkPad
Vista-compatible BIOSes with standard ACPI backlight level control.

Signed-off-by: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
Cc: Matthew Garrett <mjg59@srcf.ucam.org>
Cc: Yves-Alexis Perez <corsac@debian.org>
Signed-off-by: Len Brown <len.brown@intel.com>
This commit is contained in:
Henrique de Moraes Holschuh 2008-10-18 14:23:55 -03:00 committed by Len Brown
parent 396293237c
commit d64c81c4ce
1 changed files with 11 additions and 0 deletions
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11
drivers/misc/thinkpad_acpi.c
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@ -838,6 +838,13 @@ static int parse_strtoul(const char *buf,
return 0;
}
static void tpacpi_disable_brightness_delay(void)
{
if (acpi_evalf(hkey_handle, NULL, "PWMS", "qvd", 0))
printk(TPACPI_NOTICE
"ACPI backlight control delay disabled\n");
}
static int __init tpacpi_query_bcl_levels(acpi_handle handle)
{
struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
@ -2139,6 +2146,8 @@ static int __init hotkey_init(struct ibm_init_struct *iibm)
if (!tp_features.hotkey)
return 1;
tpacpi_disable_brightness_delay();
hotkey_dev_attributes = create_attr_set(13, NULL);
if (!hotkey_dev_attributes)
return -ENOMEM;
@ -2512,6 +2521,8 @@ static void hotkey_suspend(pm_message_t state)
static void hotkey_resume(void)
{
tpacpi_disable_brightness_delay();
if (hotkey_mask_get())
printk(TPACPI_ERR
"error while trying to read hot key mask "