#40 Unichrome R30 crashes without via-agp kernel module loaded

[Jamie Lokier]

The Unichrome R30 driver depends on the "via-agp"
kernel module to be loaded, if AGP is enabled in the X
configuration. However, if the kernel module is not
loaded then Unichrome proceeds to do all sorts of odd
things: rendering bugs, pausing the whole computer for
seconds at a time, crashing when X is killed (every
time), and spewing these sort of messages to the kernel
log:

[drm:via_cmdbuf_jump] *ERROR* via_cmdbuf_jump failed
[drm:via_cmdbuf_wait] *ERROR* via_cmdbuf_wait timed out
hw 180 cur_addr 30
+next_addr 80230
[drm:via_cmdbuf_wait] *ERROR* via_cmdbuf_wait timed out
hw 180 cur_addr 100
+next_addr 80300
[drm:via_cmdbuf_wait] *ERROR* via_cmdbuf_wait timed out
hw 180 cur_addr 0
+next_addr 80100
[drm:via_cmdbuf_jump] *ERROR* via_cmdbuf_jump failed
[drm:via_cmdbuf_wait] *ERROR* via_cmdbuf_wait timed out
hw 180 cur_addr 30
+next_addr 80230
[drm:via_cmdbuf_wait] *ERROR* via_cmdbuf_wait timed out
hw 180 cur_addr 100
+next_addr 80300

This is all caused by enabling AGP in xorg.conf, and
not loading the "via-agp" kernel module.

The bug is that Unichrome proceeds to try and use AGP
anyway. It should either demand-load the module, or
complain and refuse to use AGP when it's not loaded.

The workaround is to manually load the module before
starting X, compile it directly into the kernel, or not
enable AGP in xorg.conf.

Thanks! :)
-- Jamie Lokier

[Luc Verhaegen]

Logged In: YES
user_id=220099

I believe, without looking into drm, that this was already
fixed there. I'm not able to reproduce it.

But yes, that code is indeed a mess, and i'll change it.