Steps to reproduce (Toshiba Satellite R630 laptop, ArchLinux x86_64): 1. modprobe toshiba_backlight (actualy it's autoloaded during boot), 2. observe Fn+F6 and Fn+F5 keys not affecting backlight brightness. This happens in all following cases: - no acpi_backlight in kernel boot line, - acpi_backlight=vendor, - acpi_backlight=legacy. It's still possible to adjust brightness via /sys/class/backlight/ interface. ACPI events on key presses are still happening. Once toshiba_acpi module is loaded, unloading it without reboot doesn't help. After loading & unloading no ACPI events will be generated anymore. Blacklisting toshiba_acpi module fixes the problem with either options: - no acpi_backlight in kernel boot line, - or acpi_backlight=legacy. Having acpi_backlight=vendor causes the same problem even with blacklisted toshiba_acpi. Not sure if it is relevant, but #43168 and #21012 are describing somehow similar issues.
I have run bisect and found out commit introducing the problem: commit 29cd293f9f8cd76444657622980010b9364b1de6 Author: Seth Forshee <seth.forshee@canonical.com> Date: Wed Jan 18 13:44:09 2012 -0600 toshiba_acpi: Support alternate hotkey interfaces There are two types of problems that prevent hotkeys from working on many of the machines supported by toshiba_acpi. The first of these is the lack of a functioning SCI for hotkey events. For these machines it is possible to filter the Fn keypresses from the keyboard and generate a notification by executing the ACPI NTFY method. The second problem is a lack of support for HCI_SYSTEM_EVENT, which is used for reading the hotkey scancodes. On these machines the scancodes can be read by executing the ACPI NTFY method. This patch fixes both problems by installing an i8042 filter when the NTFY method is present to generate notifications and by detecting which of INFO or HCI_SYSTEM_EVENT is supported for reading scancodes. If neither method of reading scancodes is supported, the hotkey input device is not registered. Signed-off-by: Azael Avalos <coproscefalo@gmail.com> Signed-off-by: Seth Forshee <seth.forshee@canonical.com> Signed-off-by: Matthew Garrett <mjg@redhat.com> Please let me know if I could provide additional useful information.