[Bug 58871] New: vanilla 3.9, Intel GPU: Intense LCD brightness in both fb console and X

[bugzilla-daemon at bugzilla.kernel.org]

https://bugzilla.kernel.org/show_bug.cgi?id=58871

           Summary: vanilla 3.9, Intel GPU: Intense LCD brightness in both
                    fb console and X
           Product: Drivers
           Version: 2.5
    Kernel Version: 3.9.3
          Platform: All
        OS/Version: Linux
              Tree: Mainline
            Status: NEW
          Severity: normal
          Priority: P1
         Component: Video(DRI - Intel)
        AssignedTo: intel-gfx-bugs at lists.freedesktop.org
        ReportedBy: roman.zilka at gmail.com
                CC: intel-gfx-bugs at lists.freedesktop.org
        Regression: Yes


Created an attachment (id=102671)
 --> (https://bugzilla.kernel.org/attachment.cgi?id=102671)
.config

I have an embedded Sandy Bridge Intel GPU. Booting kernel 3.9 I get an
above-normal brightness/alpha in the (external) LCD. The problem appears the
moment the kernel begins to boot in the (fb) text console and carries over to X
as well. In 3.8 the problem doesn't exist. There is no change in Xorg.0.log
when X runs under 3.8 and 3.9.

The LCD is connected to a laptop via HDMI. I can't tell for sure if the
brightness has risen in the laptop built-in LCD too - I rarely use it these
days - but my guess is that it has risen there too.

The problem persists even if I remove x2apic support and (almost) everything
under ACPI. These are the changes between 3.8.12 and 3.9.3 in the Drivers ->
Graphics area:
CONFIG_DRM_TTM=m
CONFIG_DRM_GMA500=m
CONFIG_HDMI=y

I don't load these modules anyway, though, and CONFIG_HDMI is auto-selected by
CONFIG_DRM.

Gentoo x86_64, gcc-4.6.3, xorg-server-1.13.4, xf86-video-intel-2.20.13.

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