Precision 7730 -- brightness adjustment stops working in latest BIOS

Hi Alan

I have updated BIOS to version 1.12.1 twice but brightness does not work still even in BIOS menu. I have Windows 10 PRO for workstation. In both trials i have disabled switchable graphics, actually i have disabled switchable graphic from day that i got laptop from my dealer to keep performance as high i possible. 

Only way to fix brightness problem is in to downgrade BIOS to version 1.10.1 for my hardware configuration. I have never update it through Dell Precision Optimizer, i always downloading installation files from Dell support site and install it manually.

My Precision 7730 have warranty till 2021 so should i contact to your local support service for replacement of hardware ?

From my point of wiew it seems like a problem with BIOS or EC firmware after update.

Hardware configuration:

Precision 7730

Intel Xeon E-2186M 

Nvidia Quadro P5200

@janek134927 do you have the system setup correctly in the BIOS to function with the brightness keys?

I have had other users confirm that the fix did work when they updated the BIOS.

I'll drop you a private message to get your tag details.

Alan

I am experiencing the same issue after the bios update.  All was working fine (for 6+ months) until I ran the update after the holiday.  Now the system does not respond to changes in the brightness settings.  The FN keys adjust the set point, but the set point does not actually change the display brightness.  This is the case for the slider withing windows and the slider in the bios.  This is is very likely a bios bug.  Any suggestions before reverting to the older bios version? 

@CJSAMARAS thanks for advising you are also seeing the problem after the latest BIOS update.

Can you confirm whether the you can change the brightness settings within the BIOS using the Fn keys?

Do you have the Fn key functionality set up correctly in the BIOS?

Are there any other Fn key combinations that aren't working?

I'll drop you a private message to get your service tag details.

Alan

The settings are changing values, but not applying to the screen output.  All other FN keys seem to be continue to work without issue, keyboard backlight, system volume, search, right click menu...

I also replied with my email, and service tag to the PM.

@SRSR333 your findings match what myself and my colleague in engineering replicated today with disabling switchable graphics. He is escalating back to product development team to have them investigate it further.

It's strange that it has never worked in the BIOS though. Multiple users have confirmed that it works in the BIOS and this ties in with our findings earlier. Do you have the Fn keys enabled in the BIOS settings?

With regards to Arch Linux, it's not officially certified for use on the system. We can't guarantee functionality with all features.

I'll drop you a private message to get your tag details.

Alan

Let me chime in to this discussion:

I own a Precision 7530, currently on BIOS 1.11.0. After updating to BIOS 1.12.1, I lost brightness control in Windows, when disabling graphics switching. Leaving it enabled, brightness control works, both in Windows and in the BIOS. 

Furthermore, brightness control has never, ever worked for me in the BIOS with graphics switching disabled, regardless of the BIOS version, and the screen brightness is locked at the maximum brightness. I currently have what is actually a replacement Precision 7530 unit which has a different display (AUO B156HAN06.0) to the original one (LG LP156WF6). This issue occurred in both units, and continues to occur, regardless of firmware version.

Finally, in Arch Linux (without having installed Xorg/Wayland and a desktop environment yet), pressing the Fn+brightness up/down keys throws several lines of ACPI errors:

$ [ 388.293574] ACPI BIOS Error (bug): Could not resolve symbol[\_SB.PCI0.PEG0.PEGP.BRT6.LCD], AE_NOT_FOUND (20190703/psargs-330)
[ 388.293608] ACPI Error: Aborting method \_SB.PCI0.PEG0.PEGP.BRT6 due to previous error (AE_NOT_FOUND) (20190703/psparse-529) 
[ 388.293668] ACPI Error: Aborting method \EV5 due to previous error (AE_NOT_FOUND) (20190703/psparse-529)
[ 388.293727] ACPI Error: Aborting method \SMEE due to previous error (AE_NOT_FOUND) (20190703/psparse-529)
[ 388.293786] ACPI Error: Aborting method \SMIE due to previous error (AE_NOT_FOUND) (20190703/psparse-529) 
[ 388.293845] ACPI Error: Aborting method \NEVT due to previous error (AE_NOT_FOUND) (20190703/psparse-529) 
[ 388.293903] ACPI Error: Aborting method \_SB.PCI0.LPCB.ECDV._Q66 due to previous error (AE_NOT_FOUND) (20190703/psparse-529)

This is very likely an ACPI bug in the DSDT tables of the machine, which I've attempted to fix, but to no avail. There is a detailed thread at the Linux kernel bug tracker, and it appears to be common to a lot of recent Precision notebooks, whether 75XX or 77XX, or the XPS-based 55XX.

Could you get the team to look at this, @Dell-Alan D, @DELL-John C  and co.? It would be most appreciated.

my system came with 18.04 from Dell.

@mtsn,

Thank you for your reply. My colleague who is working on this case will get back to you on this. 

@mtsn apologies for the confusion, I was unaware the system shipped with 18.04. 

Can you advise what version of the Ubuntu you are currently running on the system?

Has this issue with brightness only occurred since updating to the latest BIOS?

Do you have switchable graphics enabled or disabled in the BIOS?

With regards to your comments about myself raising this issue to engineering, we found an issue with the brightness setting not functioning when you had switchable graphics disabled. Gong by the information you have provided I'm not sure the issue is exactly the same.

Alan

@mtsn,

Dell has not tested 19.10 version. We recommend using 18.04 or 16.04.3.

Since when are you facing this issue? ^KR

I'm currently running 19.10, and my laptop doesn't have switchable graphics, since I only have the built-in graphics (Intel UHD 630 from i915). 

Hello, I use a company-owned Dell 7530 running Windows 10 Enterprise, but our IT department can't help me with this. The BIOS version is 1.11.0.

I have also the issue with changing the screen brightness using the Fn and arrow up/down key combination. While in the BIOS it works fine but in Windows it doesn't and that drives me crazy. Changing screen brightness using the slider in Windows Display settings works fine.

All other Fn key combinations for changing volume, keyboard light, aeroplane mode are working properly while in Windows.

I have read about BIOS version 1.12.1. but can't make up if this version will fix the issue..

Please advice what I can do trying to solve this, thanks.