[PATCH] ACPI: video: Add acpi_backlight=vendor quirk for Toshiba Portégé R100

[Ondrej Zary <linux@zary.sk>]

Toshiba Portégé R100 has both acpi_video and toshiba_acpi vendor
backlight driver working. But none of them gets activated as it has
a VGA with no kernel driver (Trident CyberBlade XP4m32).

The DMI strings are very generic ("Portable PC") so add a custom
callback function to check for Trident CyberBlade XP4m32 PCI device
before enabling the vendor backlight driver (better than acpi_video
as it has more brightness steps).

Fixes: 5aa9d943e9b6 ("ACPI: video: Don't enable fallback path for creating ACPI backlight by default")
Signed-off-by: Ondrej Zary <linux@zary.sk>
---
 drivers/acpi/video_detect.c | 26 ++++++++++++++++++++++++++
 1 file changed, 26 insertions(+)

diff --git a/drivers/acpi/video_detect.c b/drivers/acpi/video_detect.c
index 442396f6ed1f..31205fee59d4 100644
--- a/drivers/acpi/video_detect.c
+++ b/drivers/acpi/video_detect.c
@@ -130,6 +130,16 @@ static int video_detect_force_native(const struct dmi_system_id *d)
 	return 0;
 }
 
+static int video_detect_portege_r100(const struct dmi_system_id *d)
+{
+	struct pci_dev *dev;
+	/* Search for Trident CyberBlade XP4m32 to confirm Portégé R100 */
+	dev = pci_get_device(PCI_VENDOR_ID_TRIDENT, 0x2100, NULL);
+	if (dev)
+		acpi_backlight_dmi = acpi_backlight_vendor;
+	return 0;
+}
+
 static const struct dmi_system_id video_detect_dmi_table[] = {
 	/*
 	 * Models which should use the vendor backlight interface,
@@ -270,6 +280,22 @@ static const struct dmi_system_id video_detect_dmi_table[] = {
 		},
 	},
 
+	/*
+	 * Toshiba Portégé R100 has working both acpi_video and toshiba_acpi
+	 * vendor driver. But none of them gets activated as it has a VGA with
+	 * no kernel driver (Trident CyberBlade XP4m32).
+	 * The DMI strings are generic so check for the VGA chip in callback.
+	 */
+	{
+	 .callback = video_detect_portege_r100,
+	 .matches = {
+		DMI_MATCH(DMI_SYS_VENDOR, "TOSHIBA"),
+		DMI_MATCH(DMI_PRODUCT_NAME, "Portable PC"),
+		DMI_MATCH(DMI_PRODUCT_VERSION, "Version 1.0"),
+		DMI_MATCH(DMI_BOARD_NAME, "Portable PC")
+		},
+	},
+
 	/*
 	 * Models which need acpi_video backlight control where the GPU drivers
 	 * do not call acpi_video_register_backlight() because no internal panel
-- 
Ondrej Zary