drivers/platform: toshiba_acpi: Call HCI_PANEL_POWER_ON on resume on some models

Some Toshibas have a broken acpi-video interface for brightness control, so
far these have been using a special workaround in drivers/acpi/acpi_video.c
which gets activated by the disable_backlight_sysfs_if module-param/quirks.

The recent x86/acpi backlight refactoring has broken this workaround:
1. This workaround relies on acpi_video_get_backlight_type() returning
   acpi_video so that the acpi_video code actually runs; and
2. this relies on the actual native GPU driver to offer the sysfs
   backlight interface to userspace.

After the refactor this breaks since the native driver will no
longer register its backlight-device if acpi_video_get_backlight_type()
does not return native and making it return native breaks 1.

Keeping the acpi_video backlight handling on resume active, while not
using it to set the brightness, is necessary because it does a _BCM
call on resume which is necessary to turn the panel back on on resume.

Looking at the DSDT shows that this _BCM call results in a Toshiba
HCI_SET HCI_LCD_BRIGHTNESS call, which turns the panel back on.

This commit makes toshiba_acpi do a HCI_SET HCI_PANEL_POWER_ON call
on resume on the affected models, so that the (now broken)
acpi_video disable_backlight_sysfs_if workaround will no longer
be necessary.

Note this uses HCI_PANEL_POWER_ON instead of HCI_LCD_BRIGHTNESS
to avoid changing the configured brightness level.
Tested-by: Arvid Norlander <lkml@vorpal.se>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>

drivers/platform/x86/toshiba_acpi.c

@@ -23,6 +23,7 @@
 #define PROC_INTERFACE_VERSION	1
 
 #include <linux/compiler.h>
+#include <linux/dmi.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/moduleparam.h>
@@ -52,6 +53,11 @@ MODULE_AUTHOR("John Belmonte");
 MODULE_DESCRIPTION("Toshiba Laptop ACPI Extras Driver");
 MODULE_LICENSE("GPL");
 
+int turn_on_panel_on_resume = -1;
+module_param(turn_on_panel_on_resume, int, 0644);
+MODULE_PARM_DESC(turn_on_panel_on_resume,
+	"Call HCI_PANEL_POWER_ON on resume (-1 = auto, 0 = no, 1 = yes");
+
 #define TOSHIBA_WMI_EVENT_GUID "59142400-C6A3-40FA-BADB-8A2652834100"
 
 /* Scan code for Fn key on TOS1900 models */
@@ -102,6 +108,7 @@ MODULE_LICENSE("GPL");
 #define TOS_NOT_INSTALLED		0x8e00
 
 /* Registers */
+#define HCI_PANEL_POWER_ON		0x0002
 #define HCI_FAN				0x0004
 #define HCI_TR_BACKLIGHT		0x0005
 #define HCI_SYSTEM_EVENT		0x0016
@@ -3242,6 +3249,43 @@ static const char *find_hci_method(acpi_handle handle)
 	return NULL;
 }
 
+/*
+ * Some Toshibas have a broken acpi-video interface for brightness control,
+ * these are quirked in drivers/acpi/video_detect.c to use the GPU native
+ * (/sys/class/backlight/intel_backlight) instead.
+ * But these need a HCI_SET call to actually turn the panel back on at resume,
+ * without this call the screen stays black at resume.
+ * Either HCI_LCD_BRIGHTNESS (used by acpi_video's _BCM) or HCI_PANEL_POWER_ON
+ * works. toshiba_acpi_resume() uses HCI_PANEL_POWER_ON to avoid changing
+ * the configured brightness level.
+ */
+static const struct dmi_system_id turn_on_panel_on_resume_dmi_ids[] = {
+	{
+	 /* Toshiba Portégé R700 */
+	 /* https://bugzilla.kernel.org/show_bug.cgi?id=21012 */
+	 .matches = {
+		DMI_MATCH(DMI_SYS_VENDOR, "TOSHIBA"),
+		DMI_MATCH(DMI_PRODUCT_NAME, "PORTEGE R700"),
+		},
+	},
+	{
+	 /* Toshiba Satellite/Portégé R830 */
+	 /* Portégé: https://bugs.freedesktop.org/show_bug.cgi?id=82634 */
+	 /* Satellite: https://bugzilla.kernel.org/show_bug.cgi?id=21012 */
+	 .matches = {
+		DMI_MATCH(DMI_SYS_VENDOR, "TOSHIBA"),
+		DMI_MATCH(DMI_PRODUCT_NAME, "R830"),
+		},
+	},
+	{
+	 /* Toshiba Satellite/Portégé Z830 */
+	 .matches = {
+		DMI_MATCH(DMI_SYS_VENDOR, "TOSHIBA"),
+		DMI_MATCH(DMI_PRODUCT_NAME, "Z830"),
+		},
+	},
+};
+
 static int toshiba_acpi_add(struct acpi_device *acpi_dev)
 {
 	struct toshiba_acpi_dev *dev;
@@ -3399,6 +3443,9 @@ static int toshiba_acpi_add(struct acpi_device *acpi_dev)
 	}
 #endif
 
+	if (turn_on_panel_on_resume == -1)
+		turn_on_panel_on_resume = dmi_check_system(turn_on_panel_on_resume_dmi_ids);
+
 	toshiba_wwan_available(dev);
 	if (dev->wwan_supported)
 		toshiba_acpi_setup_wwan_rfkill(dev);
@@ -3524,6 +3571,9 @@ static int toshiba_acpi_resume(struct device *device)
 			rfkill_set_hw_state(dev->wwan_rfk, !dev->killswitch);
 	}
 
+	if (turn_on_panel_on_resume)
+		hci_write(dev, HCI_PANEL_POWER_ON, 1);
+
 	return 0;
 }
 #endif