[Bugme-new] [Bug 32862] New: acer_wmi partially crashes ACPI/EC (Aspire 8930G)

[bugzilla-daemon at bugzilla.kernel.org]

https://bugzilla.kernel.org/show_bug.cgi?id=32862

           Summary: acer_wmi partially crashes ACPI/EC (Aspire 8930G)
           Product: ACPI
           Version: 2.5
    Kernel Version: 2.6.38-gentoo-r1
          Platform: All
        OS/Version: Linux
              Tree: Mainline
            Status: NEW
          Severity: high
          Priority: P1
         Component: Other
        AssignedTo: acpi_other at kernel-bugs.osdl.org
        ReportedBy: hector at marcansoft.com
        Regression: Yes


laptop model: Acer Aspire 8930G

When the acer-wmi module is loaded, parts of ACPI go haywire. The immediate
symptom is that backlight control stops working, logging messages like the
following:
kernel: ACPI Error: Method parse/execution failed
[\_SB_.PCI0.PEGP.EVGA.LCD_._BCM] (Node ffff88013fc2b820), AE_AML_INFINITE_LOOP
(20110112/psparse-536)
kernel: ACPI Error: Evaluating _BCM failed (20110112/video-365)
ACPI: Failed to switch the brightness

I suspect it's waiting for some kind of state from the EC which never arrives.

Not loading acer_wmi solves the issue and brightness control works since that
uses the ACPI video driver anyway (however, this might have other negative
consequences regarding e.g. rfkill as others have mentioned before).

However, the issue is more severe than this. After shutting down and restarting
the computer, or rebooting, the machine hangs during POST with no video and no
backlight. This persists even if more reboots are attempted. The only way to
clear this state is to disconnect AC power, and remove the battery. This is why
I suspect the EC is hanging.

acer-wmi on 2.6.37-gentoo didn't have these issues.

-- 
Configure bugmail: https://bugzilla.kernel.org/userprefs.cgi?tab=email
------- You are receiving this mail because: -------
You are on the CC list for the bug.