I want to install a new LCD panel in my Intel Core i7/HD4000-based laptop. The intended replacement is a glossy HannStar HSD173PUW1-A - to replace its original very grainy Chi Mei 173HGE. However, I have encountered a problem, not documented anywhere except its datasheet, that the HannStar has hardware-based Content Adaptive Brightness Control (CABC). This means that right from the point of booting in the BIOS, it attempts to 'intelligently' decrease the backlight as the proportion of dark pixels on the screen increases.
Suffice it to say that I cannot stand this, for reasons of both (A) distraction as whites alter in intensity of their own accord and (B) reduced quality as colours lose saturation on 'darker' screens. I have had to revert to the original super-grainy Chi Mei simply because the grain is LESS annoying than the CABC in the HannStar: grainy whites are marginally better than whites that cycle in brightness whenever I open a dark website or a Command Prompt. :/
Let's save ourselves a lot of repetition: I have tried all the usual things recommended in all the threads found by Google. These included disabling all brightness-related settings in the Intel control panel and Windows itself, uninstalling my OEM HD4000 drivers and reinstalling the latest versions, etc. - to no avail. There is no option for Automatic* Brightness in Intel Graphics, my BIOS, or anywhere else. Disabling the usually recommended things like Power Management in Intel and Windows had no effect; the auto-brightness is system-wide and occurs even in my (near-useless) OEM BIOS. This indicates it's set on the hardware level.
Indeed, having delved into the spec/datasheet - attached - for the HannStar, its CABC is enabled by a single pin on the 40-pin LVDS connector being set to low voltage/0 and disabled by high voltage/1 (this seems backwards to me, but what can ya do). Thus, I assume that to disable it, I would have to instruct the HD4000, on a system-wide level, to set this pin to high voltage. Perhaps this is what the "Automatic Brightness" in the Windows app (*edit: not Adaptive, as this is not related to ambient light levels at all) would do, but I have no such option! Therefore, I would need an Intel control panel app with the option not hidden from me - as presumably it does not detect CABC's presence - OR a way to modify this on a BIOS level.
I hope this is a feature that can be delivered. And I appreciate all comments from fellow users - as long as they're not simply asking me whether I have read the countless threads I've already read or toggling the countless options I've already toggled! ; ) Thanks in advance to all for constructive replies.
HSD173PUW1-A.pdf 315.2 K