pregnant pauses in 2-D graphics; IRQ assignment?
Motherboard: supermicro P4DCE+,
dual 2GHz Xeon CPUs, 1GB RAM
Graphics card: tried both GF4 Ti4600 and GF4 MX400
Kernel: tried RH's 2.4.18-5smp,
RH's 2.4.18-3 smp bigmem,
kernel boot options: tried "noapic", "nosmp noapic" as well as default.
XFree86: 4.2.0 as shipped with RH7.3.
NVidia drivers: tried 2880 and 4363.
AGP access: tried Option "NvAGP" "0"
and default (which gave 4x AGP via agpgart).
I've tried many, many combinations of the
but always find the following problem:
Many attempts to do things requiring 2-D
bit-blitting -- e.g. dragging an xterm
or even painting text into an xterm or
painting buttons on a GUI -- are liable to
be extremely slow, such that the entire
X server will lock up for tens of seconds at
a time. This makes it hard to type,
let alone work normally.
Curiously, 3-D opengl graphics don't
seem to suffer from this problem.
A similar system (Supermicro P4DCE+,
dual 2GHz Xeons, 2GB RAM) doesn't
have this problem.
The problem also goes away if I use
the "nv" driver instead of "nvidia",
but we really need the 3-D acceleration.
Suspicion: on the troublesome system,
the nvidia card always shares a
PCI interrupt (16) with the ethernet controller. On the well-running system,
the nvidia card has IRQ 10 to itself.
I can't seem to change the IRQ assignment
with tweaks like (since 01:00.0 is the nv card)
setpci -v -s 01:00.0 interrupt_line=12
setpci -v -s 01:00.0 interrupt_pin=2
The Ethernet is on the motherboard,
so I can't just move it to a different slot.
Anyone seen such a problem?