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Brightness (Backlight) control in Windows
Brightness (Backlight) control in Windows
Brightness control in Windows works but only if I install a graphics driver. Is it possible to control brightness without installing a graphic driver? In the BIOS, the control works without any driver.
Re: Brightness (Backlight) control in Windows
Apparently, the Linux system is done through the driver thinkpad-acpi. The documentation shows that:
Bluetooth & ThinkLight on/off you can switch using the TPFanControl application in Windows:
https://cdn1.savepice.ru/uploads/2018/1 ... b-full.png
I found the source code TPFanControl and e.g. portio.cpp have registers of Embedded Controller:
Maybe somehow using the HWDirect program ?:
https://cdn1.savepice.ru/uploads/2018/1 ... 4-full.png
I found this but I do not know how to read or write down the registers ACPI-defined port 66 commands
Code: Select all
Status
------
The features currently supported are the following (see below for
detailed description):
- Fn key combinations
- Bluetooth enable and disable
- video output switching, expansion control
- ThinkLight on and off
- CMOS/UCMS control
- LED control
- ACPI sounds
- temperature sensors
- Experimental: embedded controller register dump
- LCD brightness control
- Volume control
- Fan control and monitoring: fan speed, fan enable/disable
- WAN enable and disable
- UWB enable and disable
https://cdn1.savepice.ru/uploads/2018/1 ... b-full.png
I found the source code TPFanControl and e.g. portio.cpp have registers of Embedded Controller:
Code: Select all
// Registers of the embedded controller
#define EC_DATAPORT 0x1600 // EC data io-port 0x62
#define EC_CTRLPORT 0x1604 // EC control io-port 0x66
// Embedded controller status register bits
#define EC_STAT_OBF 0x01 // Output buffer full
#define EC_STAT_IBF 0x02 // Input buffer full
#define EC_STAT_CMD 0x08 // Last write was a command write (0=data)
// Embedded controller commands
// (write to EC_CTRLPORT to initiate read/write operation)
#define EC_CTRLPORT_READ (char)0x80
#define EC_CTRLPORT_WRITE (char)0x81
#define EC_CTRLPORT_QUERY (char)0x84
https://cdn1.savepice.ru/uploads/2018/1 ... 4-full.png
I found this but I do not know how to read or write down the registers ACPI-defined port 66 commands
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- SuperUserGeorge
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Re: Brightness (Backlight) control in Windows
Colour me curious: why wouldn't you want a graphics driver installed ?
...Knowledge is a deadly friend when no one sets the rules...(King Crimson)
Cheers,
George (your grouchy retired FlexView farmer)
FlexView AARP club members:A31p, T43pSF
Abused daily: T520, X200s
PMs requesting personal tech support will be ignored.
Cheers,
George (your grouchy retired FlexView farmer)
FlexView AARP club members:A31p, T43pSF
Abused daily: T520, X200s
PMs requesting personal tech support will be ignored.
Re: Brightness (Backlight) control in Windows
Because WinXP x64 in EFI mode does not boot on the Intel graphics driver.
WinXP runs with Universal VESA/VBE Video Display Driver but brightness control not work https://www.betaarchive.com/forum/viewt ... 7c#p434999
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- SuperUserGeorge
- Posts: 17057
- Joined: Sun Feb 25, 2007 11:28 am
- Location: Brodheadsville, Pennsylvania, USA
Re: Brightness (Backlight) control in Windows
OK anything XP 64 bit is utterly foreign to me, so I'll just wish you the best of luck in your quest.
...Knowledge is a deadly friend when no one sets the rules...(King Crimson)
Cheers,
George (your grouchy retired FlexView farmer)
FlexView AARP club members:A31p, T43pSF
Abused daily: T520, X200s
PMs requesting personal tech support will be ignored.
Cheers,
George (your grouchy retired FlexView farmer)
FlexView AARP club members:A31p, T43pSF
Abused daily: T520, X200s
PMs requesting personal tech support will be ignored.
Re: Brightness (Backlight) control in Windows
OK, I learned how to switch Thinklight. This is possible using the program RW - Read & Write Utility - I use version 64-bit 1.6.9. It is enough to change the Embedded Controller register 3B:
10 - thinklight off
12 - thinklight on
https://cdn1.savepice.ru/uploads/2018/1 ... 5-full.png
The brightness is probably not controlled by the EC. The graphic driver can control brightness. I found this topic Fix your X220 brightness keys under Windows 10 permanently but this is for Win10. I tried entry FeatureTestControl in the registry with the Universal VESA/VBE driver but unfortunately it does not work
10 - thinklight off
12 - thinklight on
https://cdn1.savepice.ru/uploads/2018/1 ... 5-full.png
The brightness is probably not controlled by the EC. The graphic driver can control brightness. I found this topic Fix your X220 brightness keys under Windows 10 permanently but this is for Win10. I tried entry FeatureTestControl in the registry with the Universal VESA/VBE driver but unfortunately it does not work

Re: Brightness (Backlight) control in Windows
Yes, this is version 14.51.11.64.5437. I tried also older drivers e.g. from Asrock H61M-DG3/USB3 - 14.51.6.64.5415 but WinXP x64 still not start. Only with Universal VESA/VBE OS start but this driver not support 3D and not work brightness control.
Re: Brightness (Backlight) control in Windows
Are you talking about VGA.SYS? There are plenty of things that one does not support, including Standby (Hibernation should work, though).
It's quite possible you are right. Modern Thinkpads do not support brightness control in BIOS, for example. It's possible that the BIOS for older Thinkpads actually implemented a routine to capture and handle the brightness control.
With these limitations, is there a point to continue running XP x64 in EFI mode, after you proved that it can be done?
Thinkpad 25 (20K7), T490 (20N3), Yoga 14 (20FY), T430s (IPS FHD + Classic Keyboard), X220 4291-4BG
X61 7673-V2V, T60 2007-QPG, T42 2373-F7G, X32 (IPS Screen), A31p w/ Ultrabay Numpad, A21m 2628-GXU
X61 7673-V2V, T60 2007-QPG, T42 2373-F7G, X32 (IPS Screen), A31p w/ Ultrabay Numpad, A21m 2628-GXU
Re: Brightness (Backlight) control in Windows
No, with Standard VGA Graphic Adapter WinXP also not start in EFI mode. I use Universal VESA/VBE - link -> VBEMP NT Project Universal VESA/VBE Video Display Driver
direct link to driver: vbempk.zip
Read this post or whole topic: Does Windows XP have EFI?
https://www.youtube.com/watch?v=YpyVbS91UiM
Brightness in X220 is controlled by ACPI. I checked it on Linux, after executing the command:
Code: Select all
echo 0 > /sys/class/backlight/intel_backlight/brightness

It is interesting that in the BIOS or WinXP it is impossible to disable the screen completely using Fn+End, while in Linux you can disable it completely. On BIOS/WinXP is 15 levels of brightness, but on Linux is 10 levels.
Last edited by tpx61 on Mon Nov 12, 2018 5:19 pm, edited 1 time in total.
Re: Brightness (Backlight) control in Windows
I looked it at already in the previous thread where you discussed it. I understand that it can be done, my question is - why would someone want to? What are the advantages over running it in "Legacy" mode?tpx61 wrote: ↑Mon Nov 12, 2018 11:33 amRead this post or whole topic: Does Windows XP have EFI?
https://www.youtube.com/watch?v=YpyVbS91UiM
Thinkpad 25 (20K7), T490 (20N3), Yoga 14 (20FY), T430s (IPS FHD + Classic Keyboard), X220 4291-4BG
X61 7673-V2V, T60 2007-QPG, T42 2373-F7G, X32 (IPS Screen), A31p w/ Ultrabay Numpad, A21m 2628-GXU
X61 7673-V2V, T60 2007-QPG, T42 2373-F7G, X32 (IPS Screen), A31p w/ Ultrabay Numpad, A21m 2628-GXU
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- Sophomore Member
- Posts: 198
- Joined: Mon Aug 20, 2018 9:55 pm
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Re: Brightness (Backlight) control in Windows
Your going to need the driver to get the brightness control to work properly.
Daily Driver: lenovo T440p i5 20AW-S41V00
Collection: lenovo T61 C2D 6460-7EU, IBM T21 P-III 2647-6AU, IBM T20 P-III 2647-44U, IBM X20 P-III 2662-38U, IBM 380Z P-II 2635-JBU
Collection: lenovo T61 C2D 6460-7EU, IBM T21 P-III 2647-6AU, IBM T20 P-III 2647-44U, IBM X20 P-III 2662-38U, IBM 380Z P-II 2635-JBU
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