[ibm-acpi-devel] [PATCH 19/21] ACPI: ibm-acpi: work around backlight poweroff on module removal

[Henrique de M. H. <hm...@hm...>]

From: Henrique de Moraes Holschuh <hm...@hm...>

This patch  works around an annoying behaviour in the backlight class, th=
at
would reset the screen to brightness and power level 0 on module unload.

Please refer to http://thread.gmane.org/gmane.linux.acpi.devel/19712 for
details.

Signed-off-by: Henrique de Moraes Holschuh <hm...@hm...>
---

 drivers/acpi/ibm_acpi.c |    7 +++++++
 1 files changed, 7 insertions(+), 0 deletions(-)

diff --git a/drivers/acpi/ibm_acpi.c b/drivers/acpi/ibm_acpi.c
index dab3fd1..4299f43 100644
--- a/drivers/acpi/ibm_acpi.c
+++ b/drivers/acpi/ibm_acpi.c
@@ -1732,6 +1732,13 @@ static int brightness_init(void)
 static void brightness_exit(void)
 {
 	if (ibm_backlight_device) {
+		/* FIXME: can be removed when sanity returns to backlight_device_unreg=
ister */
+		if (likely(ibm_backlight_device->props)) {
+			down(&ibm_backlight_device->sem);
+			ibm_backlight_device->props->update_status =3D NULL;
+			up(&ibm_backlight_device->sem);
+		}
+
 		backlight_device_unregister(ibm_backlight_device);
 		ibm_backlight_device =3D NULL;
 	}