On Wed, Jul 25, 2012 at 01:38:09PM -0400, alexdeucher@gmail.com wrote:
From: Alex Deucher alexander.deucher@amd.com
Add a new header that defines the AMD ACPI interface used for laptops, PowerXpress, and chipset specific functionality and update the current code to use it.
Great! Now my DSDT makes sense ;)
Todo:
- properly verify the ACPI interfaces
- hook up and handle ACPI notifications
I see a problem here, I've hacked up a standalone test module, but:
+#define ATIF_FUNCTION_GET_SYSTEM_PARAMETERS 0x1
[...]
- flags
- bits 1:0:
- 0 - Notify(VGA, 0x81) is not used for notification
- 1 - Notify(VGA, 0x81) is used for notification
My system has this bit set, and the brightness control method does send the notification. My module register itself with register_acpi_notifier and gets 2 notifications, one with ACPI_VIDEO_NOTIFY_PROBE (0x81) and the other with ACPI_VIDEO_NOTIFY_INC_BRIGHTNESS (or DEC, depending on what I press).
The standard acpi "video" module, however, in response to ACPI_VIDEO_NOTIFY_PROBE generates a key press sending KEY_SWITCHVIDEOMODE.
This greatly confuses KDE which messes up my dual screen configuration; I guess that the spurious KEY_SWITCHVIDEOMODE may be problematic also with other DEs...
In more detail what happens is the following: - I press the brightness hotkey, firmware generates a notification on the relevant device (_SB.PCI0.PEG0.VGA.LCD) - ACPI video module gets the ACPI_VIDEO_NOTIFY_{DEC,INC}_BRIGHTNESS notification and tries to adjust the brightness with acpi_video_device_lcd_set_level, which in turns calls _BCM - _BCM sets the relevant bits in the AMD-specific structure and does a Notify (VGA, 0x81) - again ACPI video module gets the nodification (in this case ACPI_VIDEO_NOTIFY_PROBE), re-enumerated and send KEY_SWITCHVIDEOMODE - KDE seems this and muck with the screen configuration :( - meanwhile the brightness notification is propagated, the hypothetical radeon driver does its magic to adjust the screen.
My first idea would be to make ACPI_VIDEO_NOTIFY_PROBE also call to the acpi notifier chain, and allow the handlers to veto the key press (like it's done for ACPI_VIDEO_NOTIFY_SWITCH).
Zhang Rui what do you think about this?
The other missing bit is how to actually change the brightness... Alex, do you know what registers to poke?
My card is a:
01:00.0 VGA compatible controller [0300]: Advanced Micro Devices [AMD] nee ATI Thames XT/GL [Radeon HD 600M Series] [1002:6840]
on a Toshiba L855.
Luca