[PATCH 1/1][SRU][M] UBUNTU: SAUCE: ACPI: video: Dell AIO UART backlight detection

[AceLan Kao]

From: "Chia-Lin Kao (AceLan)" <acelan.kao at canonical.com>

BugLink: https://launchpad.net/bugs/2008882

The similar functionality has been reverted by below commit as the
function acpi_video_set_dmi_backlight_type() has been removed from
upstream.
2a773621f3495 ("UBUNTU: SAUCE: platform/x86: dell-uart-backlight: remove acpi_video_set_dmi_backlight_type()")

Now, we use new way to auto detect the Dell AIO platforms which
contains "DELL0501" HID.

Signed-off-by: Chia-Lin Kao (AceLan) <acelan.kao at canonical.com>
---
 drivers/acpi/video_detect.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/acpi/video_detect.c b/drivers/acpi/video_detect.c
index 18cc08c858cf2..7351d87e962c7 100644
--- a/drivers/acpi/video_detect.c
+++ b/drivers/acpi/video_detect.c
@@ -799,6 +799,7 @@ enum acpi_backlight_type __acpi_video_get_backlight_type(bool native, bool *auto
 	static DEFINE_MUTEX(init_mutex);
 	static bool nvidia_wmi_ec_present;
 	static bool apple_gmux_present;
+	static bool dell_uart_backlight_present;
 	static bool native_available;
 	static bool init_done;
 	static long video_caps;
@@ -813,6 +814,7 @@ enum acpi_backlight_type __acpi_video_get_backlight_type(bool native, bool *auto
 				    &video_caps, NULL);
 		nvidia_wmi_ec_present = nvidia_wmi_ec_supported();
 		apple_gmux_present = apple_gmux_detect(NULL, NULL);
+		dell_uart_backlight_present = acpi_dev_found("DELL0501");
 		init_done = true;
 	}
 	if (native)
@@ -843,6 +845,9 @@ enum acpi_backlight_type __acpi_video_get_backlight_type(bool native, bool *auto
 	if (apple_gmux_present)
 		return acpi_backlight_apple_gmux;
 
+	if (dell_uart_backlight_present)
+		return acpi_backlight_vendor;
+
 	/* Use ACPI video if available, except when native should be preferred. */
 	if ((video_caps & ACPI_VIDEO_BACKLIGHT) &&
 	     !(native_available && prefer_native_over_acpi_video()))
-- 
2.34.1