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

[Alex Deucher]

On Thu, Aug 2, 2012 at 12:33 PM, Alex Deucher <alexdeucher at gmail.com> wrote:
> On Thu, Aug 2, 2012 at 12:31 PM, Luca Tettamanti <kronos.it at gmail.com> wrote:
>> On Thu, Aug 2, 2012 at 5:03 PM, Alex Deucher <alexdeucher at gmail.com> wrote:
>>> I admit I'm not really an ACPI expert, but thinking about this more,
>>> I'm wondering if maybe we should just send the appropriate brightness
>>> change, switch display, etc. event to userspace rather than handling
>>> it directly in the radeon driver, then let userspace callback down via
>>> the bl interface, etc.  With backlight for example, does handling it
>>> in the kernel driver as per your patch prevent userspace from seeing
>>> the brightness up/down event?  Wouldn't that break things like OSD
>>> brightness displays and such?
>>
>> No, the event is sent to userspace by the standard ACPI video driver,
>> it works as before.
>> Changing brightness usually goes like this:
>> 1) user presses a hotkey
>> 2) a notification is generated (0x86 or 0x87)
>> 3) video.ko handles the notification and calls into ACPI to change the
>> level (_BCM) and firmware does its magic
>> 4) a key press (brightness up/down) is sent to userspace
>>
>> With ATIF step 3 does not actually change the brightness, it just send
>> out another event (VIDEO_PROBE, or one of the device specific ones) so
>> we need to take care of that too. The rest of the process, including
>> the delivery of the key presses, stays the same.

Updated tree with fixes to a few existing patches and improved support
for ATPX and initial support for ATCS:
http://cgit.freedesktop.org/~agd5f/linux/?h=acpi_patches

Alex