Re: [PATCH] drm/radeon: add new AMD ACPI header and update relevant code

[joeyli <jlee@suse.com>]

於 四，2012-07-26 於 23:31 -0400，Alex Deucher 提到：
> On Thu, Jul 26, 2012 at 10:50 PM, joeyli <jlee@suse.com> wrote:
> > 於 四，2012-07-26 於 14:58 +0200，Luca Tettamanti 提到：
> >> - 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).
> >
> > I welcome this approach!
> >
> > On some ATI machine's DSDT also issue ACPI_VIDEO_NOTIFY_PROBE when
> > AC-power unplug, because BIOS want to nodify video driver do some power
> > saving stuff.
> > It causes KEY_SWITCHVIDEOMODE issued by acpi/video driver when AC-power
> > unplug.
> >
> > At least acpi/video driver need to know this 0x81 event is filed by BIOS
> > to radeon-acpi for notify but not do video mode switch. That means the
> > radeon drm need take the video switch responsibility.
> 
> Probably we'd just want the radeon acpi handler to just forward the
> events to userspace so that the user can choose what to do with it
> (xrandr command, etc.), otherwise we'll need to define policy in the
> driver.
> 
> Alex
> 

Any kernel module can issue KEY_SWITCHVIDEOMODE to user space, then
gnome-settings-daemon(on Gnome) and  krandr(on KDE) will call xrandr
library to switch video mode.


The 0x81 ACPI event for acpi/video driver is ACPI_VIDEO_NOTIFY_PROBE,
means need issue KEY_SWITCHVIDEOMODE. But, 0x81 for radeon is a general
notification event.
I didn't see probe state in GET_SYSTEM_BIOS_REQUESTS, how can we
distinguish this 0x81 is a ACPI_VIDEO_NOTIFY_PROBE or a ATI general
notification event?

+ * flags
+ * bits 1:0:
+ * 0 - Notify(VGA, 0x81) is not used for notification
+ * 1 - Notify(VGA, 0x81) is used for notification

Per the above flags, when we detect bit set to 1, means 0x81 used for radeon-acpi
to be a general notification event. My question is: what's the event number for
ACPI_VIDEO_NOTIFY_PROBE on this AMD/ATI machine when 0x81 not available for acpi/video?


Thanks a lot!
Joey Lee

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