what is df -h , your root enough space ? atleast 10% of more free ?
Ok. Almost good news 
I can login like before (getting rid of prime and optimus helped) but the only downside is now my nvidia card is not being used (only integrated intel).
Glad we hear some good news from ya’
If I were you I’d give a last go, installing nouveau drivers then, maybe your nvidia is too old to be supported by the propietary drivers, here’s an all in all guide for nvidia, including the installation of nouveau too.
Hope it helps.
you used optimus-manager?, how long ytou didnt update?
probably needed a rebuild since some weeks ago python is updated… then you get idd black too… or use nvidia-prime from repo
somewhere in forum is also Nvidia legacy users (470xx 390xx) GCC broke dkms build on AUR if you have a older one…
@PotatoBeet can you please clarify what is not working? 3d accel in general, games or encoding/decoding.
Regarding nouveau driver, the card has worse support with it then with closed source driver. It (still) can not reclock maxwell cards and performance will be worse.
Can we see the output of
DRI_PRIME=pci-0000_03_00_0 __VK_LAYER_NV_optimus=NVIDIA_only __GLX_VENDOR_LIBRARY_NAME=nvidia glxinfo -B
Again, this card is supported with nvidia driver 5xx and it does not need optimus-manager at all. The only thing I am not sure about is that if it is 3d accelerator only card or full vga device. lspci -nn can confirm that, but I think it’s just a 3D accelerator because of PCI bus id
BRARY_NAME=nvidia glxinfo -B
name of display: :0
X Error of failed request: BadValue (integer parameter out of range for operation)
Major opcode of failed request: 156 (NV-GLX)
Minor opcode of failed request: 6 ()
Value in failed request: 0x0
Serial number of failed request: 96
Current serial number in output stream: 96
And lspci -nn
00:00.0 Host bridge [0600]: Intel Corporation Haswell-ULT DRAM Controller [8086:0a04] (rev 0b)
00:02.0 VGA compatible controller [0300]: Intel Corporation Haswell-ULT Integrated Graphics Controller [8086:0a16] (rev 0b)
00:03.0 Audio device [0403]: Intel Corporation Haswell-ULT HD Audio Controller [8086:0a0c] (rev 0b)
00:14.0 USB controller [0c03]: Intel Corporation 8 Series USB xHCI HC [8086:9c31] (rev 04)
00:16.0 Communication controller [0780]: Intel Corporation 8 Series HECI #0 [8086:9c3a] (rev 04)
00:1b.0 Audio device [0403]: Intel Corporation 8 Series HD Audio Controller [8086:9c20] (rev 04)
00:1c.0 PCI bridge [0604]: Intel Corporation 8 Series PCI Express Root Port 3 [8086:9c14] (rev e4)
00:1c.3 PCI bridge [0604]: Intel Corporation 8 Series PCI Express Root Port 4 [8086:9c16] (rev e4)
00:1c.4 PCI bridge [0604]: Intel Corporation 8 Series PCI Express Root Port 5 [8086:9c18] (rev e4)
00:1d.0 USB controller [0c03]: Intel Corporation 8 Series USB EHCI #1 [8086:9c26] (rev 04)
00:1f.0 ISA bridge [0601]: Intel Corporation 8 Series LPC Controller [8086:9c43] (rev 04)
00:1f.2 SATA controller [0106]: Intel Corporation 8 Series SATA Controller 1 [AHCI mode] [8086:9c03] (rev 04)
00:1f.3 SMBus [0c05]: Intel Corporation 8 Series SMBus Controller [8086:9c22] (rev 04)
01:00.0 Ethernet controller [0200]: Realtek Semiconductor Co., Ltd. RTL8111/8168/8211/8411 PCI Express Gigabit Ethernet Controller [10ec:8168] (rev 10)
02:00.0 Network controller [0280]: Intel Corporation Wireless 3160 [8086:08b4] (rev 93)
03:00.0 3D controller [0302]: NVIDIA Corporation GM108M [GeForce 840M] [10de:1341] (rev a2)
Everything works. Just when i want to run some games (that runs better on nvidia card) i need to start it with the prime-run command. Previous solution with optimus made nvidia run all the time (i don’t care about power consumption). So the ideal way would be to run nvidia permanent
Optimus manager can stil work…with prime-run can set preferences of steam prime-run %command%. Whatever you u use in steam with linux game use menu editor of kde… Also for older drivers is always good on the watch