This question is an exact duplicate of:

for some reason, Steam became too slow today.

I already tried update and upgrade, but the problem is still there. I think that is something wrong with xserver-xorg-video-intel.

Some informations:


   descrição: VGA compatible controller
   produto: 3rd Gen Core processor Graphics Controller
   fabricante: Intel Corporation
   ID físico: 2
   informações do barramento: pci@0000:00:02.0
   versão: 09
   largura: 64 bits
   clock: 33MHz
   capacidades: msi pm vga_controller bus_master cap_list rom
   configuração: driver=i915 latency=0
   recursos: irq:46 memória:f7800000-f7bfffff memória:e0000000-efffffff porta de E/S:f000(tamanho=64)

glxinfo | grep render

direct rendering: Yes

GLX_MESA_multithread_makecurrent, GLX_MESA_query_renderer, 

OpenGL renderer string: Gallium 0.4 on llvmpipe (LLVM 3.4, 256 bits)

GL_MESA_ycbcr_texture, GL_NV_blend_square, GL_NV_conditional_render, 

marked as duplicate by elmato, Daniel Foré, Gilles 'SO- stop being evil', Ravan, Lewis Goddard Oct 21 '15 at 13:45

This question was marked as an exact duplicate of an existing question.