Case study on screen brightness issue (which is in progress)
Initial state:
Lenovo Thinkpad W520 type 4282
Win 7 x64 installed
BIOS set for Optima mode
Thinkpad PM driver ver 1.65.5.20 installed
ThinkVantage Power Manager 3.67 installed
nVIDIA driver 296.35 installed
Intel Video drivers installed
HotKeys Integration installed (including Fn on screen display)
At this point, everything worked OK, except it seemed that the nVIDIA Q 1000M would only work with an external monitor (it did not seem to power or "connect to" the Thinkpad LCD screen. This seemed to be "by design".)
Change introduced to the system:
Went into BIOS settings and made 2 changes:
1. Changed video to discrete
2. Turned Optimus OFF
Coming back into Windows, the nVidia video chip was redetected, the video drivers reinstalled, and LCD display was not properly recognized (seen as 800x600 only). I manually reinstalled the display inf, reinstalled nVidia drivers and rebooted.
Second boot was more normal. Display was detected, back to 1920x1080, and video driver seemed normal.
At this point, I noticed the "could not make screen bright / dim" issue which this thread is primarily concerned with. Not only did the screen not get bright/dim, but the on screen display (hotkeys integration) had been lost -- even the keyboard light on screen glyph wouldn't appear, although Fn + PgUp did toggle light on/off.
Attempted corrections:
1. Uninstalled and reinstalled Power Management software (but not the PM driver, as I hadn't found this forum, yet)
2. Uninstalled and reinstalled video drivers, monitor, function keys integration, ThinkVantage system updater
Results: Eventually, I regained the on screen display that I was trying to brighten / dim the screen, but the screen's backlight did not change.
Attempted correction:
1. Went back to BIOS screen and set things back the way they had been, to use integrated + discrete video, with Optimus ON.
Results: no change with regards to inability to brighten/dim display
Tried changing brightness from the "Screen brightness" slider at bottom of Power Options Control Panel. No change.
-- At this point, I found this thread --
1. Tried closing them opening case - no change
2 Uninstalled Thinkpad PM driver. Instantly, before even rebooting, while the Fn Hot Keys no longer displays on screen, the bright/dim functions are back.
3. Rebooted, reinstalled Thinkpad PM Driver.. Can still make display bright/dim, but still no onscreen display.
4. Uninstalled ThinkVantage Power Manager, Uninstalled Thinkpad PM driver, rebooted. Reinstalled Thinkpad PM driver and ThinkVantage Power manager. (Tried to re-install the patch as well, but was told "not needed")
Results:
Back to original conditions. Integrated Video on ThinkPad LCD screen, Discrete video on external VGA port, Fn Hotkeys back to fully functional (includes on screen display of glyphs.)
However, I still want to force the discrete video chip to drive the onboard LCD screen.
Attempt number two:
Uninstalled ThinkVantage Power Manger
Uninstalled Thinkpad PM driver
Booted to BIOS, where set video to discrete chip and turned Optimus OFF
Once back in WIndows, installed Thinkpad PM drivers, rebooted, then installed ThinkVantage Power Management software.
Result: On screen display of glyphs back. The system THINKS I'm brightening / dimming the screen, but the LCD back light remains at constant level. Same with using the slider in the Power Options Control panel: on screen glyph shows level going up/down, but backlight remains constant.
Next step: uninstalled Thinkpad PM Device driver (from the Device Manager) - including checking "delete the device driver"
Am rebooting, now, and will continue this post once computer is back.
