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ACPI: video: Drop should_check_lcd_flag()

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Since commit 3dbc80a3e4 ("ACPI: video: Make backlight class device
registration a separate step (v2)") acpi_video# backlights are no longer
automatically registered. Instead they now only get registered when
the GPU/KMS driver calls acpi_video_register_backlight() which it only
does when it has detected an internal LCD panel.

This fixes the issue of sometimes a non-working acpi_video# backlight
showing up on Desktops / HDMI-sticks without an internal LCD display
in a more complete and robust manner then the LCD flag check which
gets enabled by the should_check_lcd_flag() helper does.

Therefor the should_check_lcd_flag() helper is no longer necessary.

The lcd_only flag itself is still necessary to only register
a single backlight device (for the right output) on the ESPRIMO Mobile
M9410 which has 2 ACPI video connector nodes with a _BCM control method,
which is the issue for which the flag was originally introduced in
commit e50b9be14a ("ACPI / video: only register backlight for LCD
device").

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This commit is contained in:
Hans de Goede
2023-11-15 18:48:11 +01:00
committed by Rafael J. Wysocki
parent 52304886ea
commit c7add369b4
1 changed files with 1 additions and 55 deletions
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drivers/acpi/acpi_video.c
+1 -55
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@@ -67,7 +67,7 @@ MODULE_PARM_DESC(hw_changes_brightness,
static bool device_id_scheme = false;
module_param(device_id_scheme, bool, 0444);
static int only_lcd = -1;
static int only_lcd;
module_param(only_lcd, int, 0444);
static bool may_report_brightness_keys;
@@ -2141,57 +2141,6 @@ static int __init intel_opregion_present(void)
return opregion;
}
/* Check if the chassis-type indicates there is no builtin LCD panel */
static bool dmi_is_desktop(void)
{
const char *chassis_type;
unsigned long type;
chassis_type = dmi_get_system_info(DMI_CHASSIS_TYPE);
if (!chassis_type)
return false;
if (kstrtoul(chassis_type, 10, &type) != 0)
return false;
switch (type) {
case 0x03: /* Desktop */
case 0x04: /* Low Profile Desktop */
case 0x05: /* Pizza Box */
case 0x06: /* Mini Tower */
case 0x07: /* Tower */
case 0x10: /* Lunch Box */
case 0x11: /* Main Server Chassis */
return true;
}
return false;
}
/*
* We're seeing a lot of bogus backlight interfaces on newer machines
* without a LCD such as desktops, servers and HDMI sticks. Checking the
* lcd flag fixes this, enable this by default on any machines which are:
* 1. Win8 ready (where we also prefer the native backlight driver, so
* normally the acpi_video code should not register there anyways); *and*
* 2.1 Report a desktop/server DMI chassis-type, or
* 2.2 Are an ACPI-reduced-hardware platform (and thus won't use the EC for
backlight control)
*/
static bool should_check_lcd_flag(void)
{
if (!acpi_osi_is_win8())
return false;
if (dmi_is_desktop())
return true;
if (acpi_reduced_hardware())
return true;
return false;
}
int acpi_video_register(void)
{
int ret = 0;
@@ -2205,9 +2154,6 @@ int acpi_video_register(void)
goto leave;
}
if (only_lcd == -1)
only_lcd = should_check_lcd_flag();
dmi_check_system(video_dmi_table);
ret = acpi_bus_register_driver(&acpi_video_bus);