Eu também tive esse problema com meu Dell E6520 com a Nvidia NVS 4200M (problema gráfico).
Procure por "Drivers adicionais" em unidade e lá mudou de "nouveau" para "proprietário, testado".
Às vezes, enquanto navega / lê um PDF / o que quer que o Ubuntu congele completamente. Eu não consigo controlar o touchpad nem o teclado, então eu uso a combinação Alt + Stamp + R + E + I + S + U + B para reiniciá-lo.
Alguma sugestão sobre como corrigir isso? Obrigado
EDIT 2:
Meu laptop é um Asus K53S.
Informação do motorista:
ale@ale-K53SC:~$ ubuntu-drivers devices
== /sys/devices/pci0000:00/0000:00:01.0/0000:01:00.0 ==
vendor : NVIDIA Corporation
model : GF119M [GeForce GT 520MX]
modalias : pci:v000010DEd00001051sv00001043sd00001762bc03sc00i00
driver : nvidia-304-updates - distro non-free
driver : nvidia-331 - distro non-free recommended
driver : xserver-xorg-video-nouveau - distro free builtin
driver : nvidia-304 - distro non-free
driver : nvidia-331-updates - distro non-free
Outras informações: ale @ ale-K53SC: ~ $ lspci -b
00:00.0 Host bridge: Intel Corporation 2nd Generation Core Processor Family DRAM Controller (rev 09)
00:01.0 PCI bridge: Intel Corporation Xeon E3-1200/2nd Generation Core Processor Family PCI Express Root Port (rev 09)
00:02.0 VGA compatible controller: Intel Corporation 2nd Generation Core Processor Family Integrated Graphics Controller (rev 09)
00:16.0 Communication controller: Intel Corporation 6 Series/C200 Series Chipset Family MEI Controller #1 (rev 04)
00:1a.0 USB controller: Intel Corporation 6 Series/C200 Series Chipset Family USB Enhanced Host Controller #2 (rev 05)
00:1b.0 Audio device: Intel Corporation 6 Series/C200 Series Chipset Family High Definition Audio Controller (rev 05)
00:1c.0 PCI bridge: Intel Corporation 6 Series/C200 Series Chipset Family PCI Express Root Port 1 (rev b5)
00:1c.1 PCI bridge: Intel Corporation 6 Series/C200 Series Chipset Family PCI Express Root Port 2 (rev b5)
00:1c.3 PCI bridge: Intel Corporation 6 Series/C200 Series Chipset Family PCI Express Root Port 4 (rev b5)
00:1c.5 PCI bridge: Intel Corporation 6 Series/C200 Series Chipset Family PCI Express Root Port 6 (rev b5)
00:1d.0 USB controller: Intel Corporation 6 Series/C200 Series Chipset Family USB Enhanced Host Controller #1 (rev 05)
00:1f.0 ISA bridge: Intel Corporation HM65 Express Chipset Family LPC Controller (rev 05)
00:1f.2 SATA controller: Intel Corporation 6 Series/C200 Series Chipset Family 6 port SATA AHCI Controller (rev 05)
00:1f.3 SMBus: Intel Corporation 6 Series/C200 Series Chipset Family SMBus Controller (rev 05)
01:00.0 VGA compatible controller: NVIDIA Corporation GF119M [GeForce GT 520MX] (rev a1)
03:00.0 Network controller: Intel Corporation Centrino Wireless-N 100
04:00.0 USB controller: ASMedia Technology Inc. ASM1042 SuperSpeed USB Host Controller
05:00.0 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller (rev 06)'
Eu também tive esse problema com meu Dell E6520 com a Nvidia NVS 4200M (problema gráfico).
Procure por "Drivers adicionais" em unidade e lá mudou de "nouveau" para "proprietário, testado".
Acontece comigo também. Eu apenas pressiono ctrl + alt + f1 e depois ctrl + alt + f7 e funciona novamente. É muito estranho.