platform/x86: thinkpad_acpi: not loading brightness_init when _BCL invalid

BugLink: https://bugs.launchpad.net/bugs/1892010
When _BCL invalid, disable thinkpad_acpi backlight brightness control.

brightness_enable is already checked at the beginning.
Most new thinkpads are using GPU driver to control brightness now,
print notice when enabled brightness control even when brightness_enable = 1.

Signed-off-by: Aaron Ma <aaron.ma@canonical.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
(cherry picked from commit 46713aeee154205fc0285b0d9ac78cb4bdf246a7)
Signed-off-by: Aaron Ma <aaron.ma@canonical.com>
Acked-by: Stefan Bader <stefan.bader@canonical.com>
Acked-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
Signed-off-by: Ian May <ian.may@canonical.com>
Signed-off-by: Kelsey Skunberg <kelsey.skunberg@canonical.com>

diff --git a/drivers/platform/x86/thinkpad_acpi.c b/drivers/platform/x86/thinkpad_acpi.c
index da794dcfdd928da30ebcc928bfc8864fa1e711a0..460584a5e86b2c033d7782450237d7afc6f0695a 100644 (file)
--- a/drivers/platform/x86/thinkpad_acpi.c
+++ b/drivers/platform/x86/thinkpad_acpi.c
@@ -6997,10 +6997,13 @@ static int __init brightness_init(struct ibm_init_struct *iibm)
                        pr_warn("Cannot enable backlight brightness support, ACPI is already handling it.  Refer to the acpi_backlight kernel parameter.\n");
                        return 1;
                }
-       } else if (tp_features.bright_acpimode && brightness_enable > 1) {
-               pr_notice("Standard ACPI backlight interface not available, thinkpad_acpi native brightness control enabled\n");
+       } else if (!tp_features.bright_acpimode) {
+               pr_notice("ACPI backlight interface not available\n");
+               return 1;
        }
 
+       pr_notice("ACPI native brightness control enabled\n");
+
        /*
         * Check for module parameter bogosity, note that we
         * init brightness_mode to TPACPI_BRGHT_MODE_MAX in order to be