Ubuntu 20.01.1 va a scatti solamente durante la schermata di login

Ho installato Ubuntu Desktop 20.04.1 LTS per architettura x64 su un vecchio server HP Proliant ML110 G5, in sostituzione a Centos 6.10, che a fine mese non verrà più supportato in maniera definitiva. Questa distribuzione funziona bene e riconosce tutto l'hardware connesso (in particolare l'embedded SATA raid di HP e il lettore nastri DAT160), però il cursore va fastidiosamente a scatti, ma solamente nella schermata di login; dopo aver effettuato il login il sistema operativo è fluido come dovrebbe. Qualcuno saprebbe darmi una mano su come risolvere questo problema? Se può essere d'aiuto, l'output di lspci è:

00:00.0 Host bridge: Intel Corporation
3200/3210 Chipset DRAM Controller (rev
01) 00:01.0 PCI bridge: Intel
Corporation 3200/3210 Chipset
Host-Primary PCI Express Bridge (rev
01) 00:1a.0 USB controller: Intel
Corporation 82801I (ICH9 Family) USB
UHCI Controller #4 (rev 02) 00:1a.1
USB controller: Intel Corporation
82801I (ICH9 Family) USB UHCI
Controller #5 (rev 02) 00:1a.2 USB
controller: Intel Corporation 82801I
(ICH9 Family) USB UHCI Controller #6
(rev 02) 00:1a.7 USB controller: Intel
Corporation 82801I (ICH9 Family) USB2
EHCI Controller #2 (rev 02) 00:1c.0
PCI bridge: Intel Corporation 82801I
(ICH9 Family) PCI Express Port 1 (rev
02) 00:1c.4 PCI bridge: Intel
Corporation 82801I (ICH9 Family) PCI
Express Port 5 (rev 02) 00:1c.5 PCI
bridge: Intel Corporation 82801I (ICH9
Family) PCI Express Port 6 (rev 02)
00:1d.0 USB controller: Intel
Corporation 82801I (ICH9 Family) USB
UHCI Controller #1 (rev 02) 00:1d.1
USB controller: Intel Corporation
82801I (ICH9 Family) USB UHCI
Controller #2 (rev 02) 00:1d.2 USB
controller: Intel Corporation 82801I
(ICH9 Family) USB UHCI Controller #3
(rev 02) 00:1d.7 USB controller: Intel
Corporation 82801I (ICH9 Family) USB2
EHCI Controller #1 (rev 02) 00:1e.0
PCI bridge: Intel Corporation 82801
PCI Bridge (rev 92) 00:1f.0 ISA
bridge: Intel Corporation 82801IR
(ICH9R) LPC Interface Controller (rev
02) 00:1f.2 RAID bus controller: Intel
Corporation SATA Controller [RAID
mode] (rev 02) 00:1f.3 SMBus: Intel
Corporation 82801I (ICH9 Family) SMBus
Controller (rev 02) 00:1f.5 IDE
interface: Intel Corporation 82801I
(ICH9 Family) 2 port SATA Controller
[IDE mode] (rev 02) 05:00.0 PCI
bridge: PLX Technology, Inc. PEX 8114
PCI Express-to-PCI/PCI-X Bridge (rev
bc) 06:08.0 SCSI storage controller:
Broadcom / LSI 53c1030 PCI-X
Fusion-MPT Dual Ultra320 SCSI (rev c1)
0d:00.0 VGA compatible controller:
Matrox Electronics Systems Ltd. MGA
G200e [Pilot] ServerEngines (SEP1)
(rev 02) 0e:00.0 Ethernet controller:
Broadcom Inc. and subsidiaries
NetXtreme BCM5722 Gigabit Ethernet PCI
Express

L'output del comando journalctl -b -p err è:

-- Logs begin at Fri 2020-11-13 12:49:51 CET, end at Fri 2020-11-13
21:26:44 CET. -- nov 13 21:22:54
server kernel: ACPI: SPCR: Unexpected
SPCR Access Width. Defaulting to byte
size nov 13 21:22:54 server kernel:
ACPI BIOS Error (bug): Failure
creating named object
[\_SB.PCI0._OSC.CAP> nov 13 21:22:54
server kernel: ACPI Error:
AE_ALREADY_EXISTS, CreateBufferField
failure (20190816/dswlo> nov 13
21:22:54 server kernel: ACPI Error:
Aborting method \_SB.PCI0._OSC due to
previous error (AE_ALR> nov 13
21:22:54 server kernel: platform
INT0800:00: failed to claim resource
0: [mem 0xff800000-0xfffff> nov 13
21:22:54 server kernel: acpi
INT0800:00: platform device creation
failed: -16 nov 13 21:22:54 server
kernel: ERST: Failed to get Error Log
Address Range. nov 13 21:22:54 server
kernel: scsi target6:0:3: Wide
Transfers Fail nov 13 21:24:50 server
gdm-password][1323]: gkr-pam: unable
to locate daemon control file nov 13
21:25:16 server pulseaudio[1354]:
GetManagedObjects() failed:
org.freedesktop.DBus.Error.NoReply>