Launchpad has imported 3 comments from the remote bug at
https://bugs.freedesktop.org/show_bug.cgi?id=45452.

If you reply to an imported comment from within Launchpad, your comment
will be sent to the remote bug automatically. Read more about
Launchpad's inter-bugtracker facilities at
https://help.launchpad.net/InterBugTracking.

------------------------------------------------------------------------
On 2012-01-31T16:54:02+00:00 Lekensteyn wrote:

Created attachment 56399
acpidump of Clevo B7130

According to Section 3.1.6 on page 40 of the ACPI Integrated Graphics
OpRegion Specification from
http://intellinuxgraphics.org/ACPI_IGD_OpRegion_%20Spec.pdf, the driver
is supposed to set the CADL field during boot and on every mode set
process. An excerpt from the spec:

============================================================
Description
This field indicates which display devices (monitors) are currently
active. A maximum of eight monitors are assumed active on a given
platform. The IDs should be the same as the enumerated monitor or
connector IDs. The graphics driver determines active monitors
during mode set times and during boot.

Driver Access
Writes: The graphics driver writes to this field on every mode set
process and during boot.
Reads: The graphics driver can read this field to update NADL.
============================================================

The struct member "cadl" from drivers/gpu/drm/i915/intel_opregion.c is
read/written nowhere. This has as implication that the field is left
uninitialized and and code that relies on that field cannot work.

So far, the affected hardware I know of are the Clevo B7130 and Clevo H150HRM. 
The brightness hotkeys emit an ACPI event for the Embedded Controller that 
checks whether an monitor is connected or not. A part of method _Q11:
============================================================
If (LEqual (^^^GFX0.CDDS (0x0410), 0x1F)) {
    If (LEqual (OEM2, Zero)) {
        If (^^^^WMI.HKDR) {
            Store (0xE0, ^^^^WMI.EVNT)
            Notify (WMI, 0xD0)
        }
    } Else {
        Notify (^^^GFX0.LCD0, 0x87)
    }
}
============================================================

The CDDS functions checks the fields of CADL, CAL2, ..., CAL8 and returns 0x1F 
if an active display equals its first argument:
============================================================
Method (CDDS, 1, NotSerialized) {
    Store (And (Arg0, 0x0F0F), Local0)
    If (LEqual (Zero, Local0)) {
        Return (0x1D)
    }
    If (LEqual (And (CADL, 0x0F0F), Local0)) {
        Return (0x1F)
    }
============================================================

This bug also makes the return value of ACPI method _DCS useless.

Reply at: https://bugs.launchpad.net/linux/+bug/806032/comments/4

------------------------------------------------------------------------
On 2012-01-31T17:01:15+00:00 Lekensteyn wrote:

Distribution: Kubuntu 11.10 AMD64
Kernel: 3.2.2 (from kernel.org)
Hardware: Intel i5 460M with HD graphics (+nvidia GT 425M, not important here)

When writing the output of the \_SB.PCI0.GFX0.LCD0._ADR value to the
DIDL field, brightness keys works.

Reply at: https://bugs.launchpad.net/linux/+bug/806032/comments/5

------------------------------------------------------------------------
On 2012-01-31T17:04:06+00:00 Lekensteyn wrote:

More machine information for an earlier bugreport related to brightness
via hotkeys is available at:
https://bugs.launchpad.net/linux/+bug/806032

Reply at: https://bugs.launchpad.net/linux/+bug/806032/comments/6


** Changed in: linux
       Status: Unknown => Confirmed

** Changed in: linux
   Importance: Unknown => Medium

-- 
You received this bug notification because you are a member of Ubuntu
Bugs, which is subscribed to Ubuntu.
https://bugs.launchpad.net/bugs/806032

Title:
  Fn + F[89] does not work for controlling brightness on Clevo laptops
  (B7130, W150HRM)

To manage notifications about this bug go to:
https://bugs.launchpad.net/linux/+bug/806032/+subscriptions

-- 
ubuntu-bugs mailing list
[email protected]
https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs

Reply via email to