Comment 22 for bug 1098216
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| Seth Forshee (sforshee) wrote Re: Regression in brightness control on Lenovo Thinkpad x230 | #22 |
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To summarize the root cause: If the OS reports itself as Windows 8, the firmware's _BCL returns a list of 101 brightness values, of which only 16 work. These 16 correspond to the values reported by _BCL if the OS does not claim to be Win8. Any brightness value passed to _BCM other than those 16 will be silently discarded without changing the brightness.