ACPI / video: Add force_none quirk for Dell OptiPlex 9020M

Dell OptiPlex 9020M is a micro PC desktop that has no built-in
LCD panel and its acpi_video does not work.

Signed-off-by: Alex Hung <[e-mail]>
Signed-off-by: Rafael J. Wysocki <[e-mail]>

drivers/acpi/video_detect.c

···
 	return 0;
 }
 
+static int video_detect_force_none(const struct dmi_system_id *d)
+{
+	acpi_backlight_dmi = acpi_backlight_none;
+	return 0;
+}
+
 static const struct dmi_system_id video_detect_dmi_table[] = {
 	/* On Samsung X360, the BIOS will set a flag (VDRV) if generic
 	 * ACPI backlight device is used. This flag will definitively break
···
 	 .matches = {
 		DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 		DMI_MATCH(DMI_PRODUCT_NAME, "Precision 7510"),
+		},
+	},
+	{
+	 .callback = video_detect_force_none,
+	 .ident = "Dell OptiPlex 9020M",
+	 .matches = {
+		DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
+		DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 9020M"),
 		},
 	},
 	{ },