Messages in this thread | | | Date | Tue, 25 Jun 2013 22:33:00 +0100 | From | Matthew Garrett <> | Subject | Re: [PATCH 0/3] Fix backlight issues on some Windows 8 systems |
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On Tue, Jun 25, 2013 at 11:30:37PM +0200, Yves-Alexis Perez wrote: > On mar., 2013-06-25 at 22:14 +0100, Matthew Garrett wrote: > > Which, as we've already established, you don't - Lenovo broke it. Your > > Thinkpad claims to have 100 available levels, and most of them don't > > work. The kernel has no way of knowing which levels work and which > > don't, so leaving this up to the kernel won't actually fix your system > > either. > > I was referring to “standardize the behaviour by leaving up to > userspace”. A lot of thinkpads (for example) (all the pre-windows 8 > ones) have a perfectly working ACPI backlight interface.
And this patchset won't alter their behaviour.
> Also, if the kernel has no way of knowing which levels work, I fail to > see how userspace can do better.
It can't. That's why this patchset disables the ACPI interface on Windows 8 systems.
> I understand that switching to intel_backlight instead of acpi_video0 > follows what Windows 8 recommends but for me it looks orthogonal to the > fact ACPI methods now have some awkward (Lenovo) or broken (Dell). I > mean, it's not the first time firmware people break some kernel > behavior. I know it's usually not easy to contact them, but shouldn't > those methods be fixed, instead of somehow blindly switching to graphic > drivers?
No. The correct answer to all firmware issues is "Are we making the same firmware calls as the version of Windows that this hardware thinks it's running". If Windows 8 doesn't make these calls, we shouldn't make these calls.
-- Matthew Garrett | mjg59@srcf.ucam.org -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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