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authorDamien Thébault <damien@dtbo.net>2018-07-18 12:06:01 +0200
committerAndy Shevchenko <andriy.shevchenko@linux.intel.com>2018-07-31 17:40:36 +0300
commit5788f77959110480486c441b912da5c2cc5fc4d2 (patch)
tree0820284b547a1f57f4a22bb72b0d62cd5ba74e61 /drivers/platform
parentc2e2a618eb7104e18fdcf739d4d911563812a81c (diff)
platform/x86: dell-laptop: Fix backlight detection
Fix return code check for "max brightness" ACPI call. The Dell laptop ACPI video brightness control is not present on dell laptops anymore, but was present in older kernel versions. The code that checks the return value is incorrect since the SMM refactoring. The old code was: if (buffer->output[0] == 0) Which was changed to: ret = dell_send_request(...) if (ret) However, dell_send_request() will return 0 if buffer->output[0] == 0, so we must change the check to: if (ret == 0) This issue was found on a Dell M4800 laptop, and the fix tested on it as well. Fixes: 549b4930f057 ("dell-smbios: Introduce dispatcher for SMM calls") Signed-off-by: Damien Thébault <damien@dtbo.net> Tested-by: Damien Thébault <damien@dtbo.net> Reviewed-by: Pali Rohár <pali.rohar@gmail.com> Reviewed-by: Mario Limonciello <mario.limonciello@dell.com> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Diffstat (limited to 'drivers/platform')
-rw-r--r--drivers/platform/x86/dell-laptop.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/platform/x86/dell-laptop.c b/drivers/platform/x86/dell-laptop.c
index f1fa8612db40..06978c14c83b 100644
--- a/drivers/platform/x86/dell-laptop.c
+++ b/drivers/platform/x86/dell-laptop.c
@@ -2185,7 +2185,7 @@ static int __init dell_init(void)
dell_fill_request(&buffer, token->location, 0, 0, 0);
ret = dell_send_request(&buffer,
CLASS_TOKEN_READ, SELECT_TOKEN_AC);
- if (ret)
+ if (ret == 0)
max_intensity = buffer.output[3];
}