Re: Need help debugging Sony Vaio VPCY2 backlight control problem

Marco Chiappero
2011-07-04T10:58:53Z

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Il 04/07/2011 10:46, Michel Alexandre Salim ha scritto:
> Hi Marco,

Hi Michel,

> Let me know if you need anything else. Once we can at least pinpoint the
> problem to the right subsystem, I'll add these attachments to the
> correct bug report.

Both this behavior and the ASL is confusing, so it's not easy to say
where is the problem exactly, but BNEN, BNCM, BNDM, BNVE are set to 0.
This affects for sure the SBRT/GBRT methods used by sony-laptop (that's
why they do not work), I can't say about _BCM/_BQC methods used by the
acpi video driver (which is preferable). However, since _BCM calls no
GFX methods and only acts on the EC, it might start to work after
setting those bits to 1. The real question is why those bits are low, is
there any issue during the EC initialization? That said, the issue
doesn't seem to belong to sony-laptop and video drivers. You can try to
temporarily fix the problem setting to 1 those bits (but it is not a
solution), just compile and run the attached program. Please report back
if it works, and if it works for both backlight controls.

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