Brightness Slider Doesn't Work after Sleep- Only after reboot

Hey guys,

        `osssssssssssssssssssso`           noah@Hamm-TECRA-R840 
       .osssssssssssssssssssssso.          -------------------- 
      .+oooooooooooooooooooooooo+.         OS: Zorin OS 15.3 x86_64 
                                           Host: TECRA R840 PT42FC-00L003 
                                           Kernel: 5.4.0-47-generic 
  `::::::::::::::::::::::.         .:`     Uptime: 3 hours, 28 mins 
 `+ssssssssssssssssss+:.`     `.:+ssso`    Packages: 2091 
.ossssssssssssssso/.       `-+ossssssso.   Shell: bash 4.4.20 
ssssssssssssso/-`      `-/osssssssssssss   Resolution: 1366x768 
.ossssssso/-`      .-/ossssssssssssssso.   DE: GNOME 3.30.2 
 `+sss+:.      `.:+ssssssssssssssssss+`    WM: GNOME Shell 
  `:.         .::::::::::::::::::::::`     WM Theme: ZorinBlue-Dark 
                                           Theme: ZorinBlue-Dark [GTK2/3] 
                                           Icons: ZorinBlue-Dark [GTK2/3] 
      .+oooooooooooooooooooooooo+.         Terminal: gnome-terminal 
       -osssssssssssssssssssssso-          CPU: Intel i5-2520M (4) @ 3.200GHz 
        `osssssssssssssssssssso`           GPU: Intel 2nd Generation Core Proce 
                                           Memory: 2008MiB / 3838MiB 


I’m running a 2011 Toshiba Tecra R840 with an Intel Core i5 2520M, Intel HD Graphics 3000, 4GB of DDR3 RAM, a 500GB Samsung EVO SATA III SSD, legacy BIOS firmware, and a 1366 by 768 HD screen. I’ve checked multiple times for proprietary 3rd party drivers from the Additional Drivers tab in the Software & Updates app, and it says I don’t have any in use and don’t need any. When I installed, I checked the option to install these proprietary drivers. I am running the laptop on a dual-boot with Windows 10 and a 128GB Zorin OS 15.3 Core partition. I have 27 GiB used out of 116 GiB according to Stacer.

So when I boot up, everything is pretty much what I’d expect, and the brightness slider and brightness function keys work fine. However, when I lock the computer or close the lid things go wrong. After waking it up from sleep, the brightness slider moves, but does not affect the brightness. The brightness is locked at the level it was at when I rebooted. The function keys don’t work either, despite showing the brightness icon on the bottom of the screen. I’ve tried to change it from the Settings app, but this has no more effect than any of the other methods. As far as I know, the only way to be able to change the brightness when this happens is to reboot. If anyone could help me figure out what the problem is, I’d be really thankful.

See if this works:
Referred from: