Commen=
t # 7
on bug 10542=
5
from MirceaKitsune
I've been testing this crash using Xonotic during the past two=
days, granted
it's a game I have a lot of experience customizing. What I found is pretty
interesting and should be a good start in shedding light on this bug.
Initially the system freeze occurred somewhere between 10 and 40 minutes. U=
pon
changing a few cvars, I seem to have almost entirely gotten rid of it: After
nearly 5 hours of continuous testing, only one lockup has taken place! Below
are the cvar overrides I added to my autoexec.cfg for the test: At least on=
e of
them had an influence... I'm still working on pinning down which, and that =
will
take several more days due to the probability rate of the issue.
r_batch_multidraw 0 // old: 1
r_batch_dynamicbuffer 0 // old: 1
r_depthfirst 0 // old: 2
gl_vbo 0 // old: 3
gl_vbo_dynamicindex 0 // old: 1
gl_vbo_dynamicvertex 0 // old: 1
r_glsl_skeletal 0 // old: 1
vid_samples 1 // old: 4
gl_texture_anisotropy 0 // old: 16
I know the issue has something to do with triangles or vertices: The crash
seems more frequent when there are a lot of players or objects present,
indicating that an increased surface count may be a contributor. I've suspe=
cted
mesh data stored on the video card to be the culprit, especially shared data
with multiple objects using one instance of a mesh from video memory. This =
is
why my bet is currently on gl_vbo (Vertex Buffer Objects /
GL_ARB_vertex_buffer_object) being the variable that made a difference... a=
gain
I still got a lockup even without it, so if anything it just heavily mitiga=
ted
the crash.
This belief is reinforced by my previous experience in Blender: The only sc=
ene
causing the GPU lockup is one where several high-poly objects share common =
mesh
data, and the crash always occurred upon me adding a Subdivision Surface to
just one of them (increasing its polygon count). It's been confirmed that a=
s of
Blender 2.77 (I have 2.79) VBO is indeed enabled in the 3D viewport. Note t=
hat
I was also using the untextured viewport, thus I doubt textures play a role.
Lastly I ruled out the possibility of overheating having anything to do with
it: During the first 3 hours in which I got no lockup, the temperature in my
room was above 26=C2=B0C. When I did get that one lockup later at night, the
temperature of my room had long dropped to 23=C2=B0C. The stress on the GPU=
was the
same at all times, absolutely no settings were changed including the map.