platform/x86: dell-laptop: Fix keyboard max lighting for Dell Latitude E6410

[ Upstream commit 68a213d325c23d39f109f4c7c824b906a7d209de ]

This machine reports number of keyboard backlight led levels, instead of
value of the last led level index. Therefore max_brightness properly needs
to be subtracted by 1 to match led max_brightness API.

Signed-off-by: Pali Rohár <pali.rohar@gmail.com>
Reported-by: Gabriel M. Elder <gabriel@tekgnowsys.com>
Link: https://bugzilla.kernel.org/show_bug.cgi?id=196913
Signed-off-by: Darren Hart (VMware) <dvhart@infradead.org>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/platform/x86/dell-laptop.c b/drivers/platform/x86/dell-laptop.c
index 2c2f02b2e08a13a7421cbcc73aaad4f8ecce0afa..167d5042a6290b2cba50cea56428873865fd70bc 100644 (file)
--- a/drivers/platform/x86/dell-laptop.c
+++ b/drivers/platform/x86/dell-laptop.c
@@ -45,6 +45,7 @@
 
 struct quirk_entry {
        u8 touchpad_led;
+       u8 kbd_led_levels_off_1;
 
        int needs_kbd_timeouts;
        /*
@@ -75,6 +76,10 @@ static struct quirk_entry quirk_dell_xps13_9333 = {
        .kbd_timeouts = { 0, 5, 15, 60, 5 * 60, 15 * 60, -1 },
 };
 
+static struct quirk_entry quirk_dell_latitude_e6410 = {
+       .kbd_led_levels_off_1 = 1,
+};
+
 static struct platform_driver platform_driver = {
        .driver = {
                .name = "dell-laptop",
@@ -270,6 +275,15 @@ static const struct dmi_system_id dell_quirks[] __initconst = {
                },
                .driver_data = &quirk_dell_xps13_9333,
        },
+       {
+               .callback = dmi_matched,
+               .ident = "Dell Latitude E6410",
+               .matches = {
+                       DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
+                       DMI_MATCH(DMI_PRODUCT_NAME, "Latitude E6410"),
+               },
+               .driver_data = &quirk_dell_latitude_e6410,
+       },
        { }
 };
 
@@ -1170,6 +1184,9 @@ static int kbd_get_info(struct kbd_info *info)
        units = (buffer->output[2] >> 8) & 0xFF;
        info->levels = (buffer->output[2] >> 16) & 0xFF;
 
+       if (quirks && quirks->kbd_led_levels_off_1 && info->levels)
+               info->levels--;
+
        if (units & BIT(0))
                info->seconds = (buffer->output[3] >> 0) & 0xFF;
        if (units & BIT(1))