[PATCH 5.19 314/717] platform/x86: msi-laptop: Fix old-ec check for backlight registering

Greg Kroah-Hartman
2022-10-22T08:55:37Z

From: Hans de Goede <hdegoede@redhat.com>

[ Upstream commit 83ac7a1c2ed5f17caa07cbbc84bad3c05dc3bf22 ]

Commit 2cc6c717799f ("msi-laptop: Port to new backlight interface
selection API") replaced this check:

if (!quirks->old_ec_model || acpi_video_backlight_support())
pr_info("Brightness ignored, ...");
else
do_register();

With:

if (quirks->old_ec_model ||
acpi_video_get_backlight_type() == acpi_backlight_vendor)
do_register();

But since the do_register() part was part of the else branch, the entire
condition should be inverted. So not only the 2 statements on either
side of the || should be inverted, but the || itself should be replaced
with a &&.

In practice this has likely not been an issue because the new-ec models
(old_ec_model==false) likely all support ACPI video backlight control,
making acpi_video_get_backlight_type() return acpi_backlight_video
turning the second part of the || also false when old_ec_model == false.

Fixes: 2cc6c717799f ("msi-laptop: Port to new backlight interface selection API")
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/20220825141336.208597-1-hdegoede@redhat.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/platform/x86/msi-laptop.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/platform/x86/msi-laptop.c b/drivers/platform/x86/msi-laptop.c
index 24ffc8e2d2d1..0960205ee49f 100644
--- a/drivers/platform/x86/msi-laptop.c
+++ b/drivers/platform/x86/msi-laptop.c
@@ -1048,8 +1048,7 @@ static int __init msi_init(void)
return -EINVAL;

/* Register backlight stuff */
-
- if (quirks->old_ec_model ||
+ if (quirks->old_ec_model &&
acpi_video_get_backlight_type() == acpi_backlight_vendor) {
struct backlight_properties props;
memset(&props, 0, sizeof(struct backlight_properties));
--
2.35.1