I have a SiS graphics card under RedHat Linux 9.0 with basic
DRI graphics support and so I can play games like chromium. But I can only do this when I am root. When I am logged on as
normal user, Chromium is very, very slow in windowed mode. As root I can play chromium in fullscreen mode with no problems. I guess this is something to do with the permissions thing. Can someone pls help me on this?

Try running it from a terminal and examinign the output was you go. It might print some error messages.

To allow mortal users to access the DRI,
you need the following in your /etc/X11/XF86Config

Section "DRI"
Mode 0666
EndSection

I did that. Still doesn't work.

How did it not work?

I do not mean to imply that it did not, but can you please provide a diagnosis of the non functioning of the program.

Did it give any warning or error messages?

Without any indication of what happened after you type

$ chromium <CarriageReturn>

it is impossible to provide any solution.

Have you ever had to have medical treatment?
Did you just say "My body is not functioning correctly" and expect
the doctor to instantly cure your ailment? No, you explained how the
problem came about and what symptoms it showed.

It's just the same with software that is ill, except the computer is
too stupid to be able to fix it's-self. :+)

When I run chromium as root, I get the following:
randomizing.
SDL initialized.
video mode set (bpp=32 RGB=888 depth=32)
-OpenGL-----------------------------------------------------
Vendor : Brian Paul
Renderer : SiS 300/630/530 DR Mode
Version : 1.2 Mesa 3.4.2
Extensions : .....

But when I run as normal user, I get:
randomizing.
SDL initialized.
video mode set (bpp=32 RGB=888 depth=32)
-OpenGL-----------------------------------------------------
Vendor : Mesa project: www.mesa3d.org
Renderer : Mesa GLX Indirect
Version : 1.3 Mesa 4.0.4
Extensions : ..........

Any help from anyone on what to do with this would be appreciated.

So when you run chromium as a nornal user, you are not accessing the DRI and so it is using Mesa GLX software rendering.

When you are running chromium as normal user, have you done started X under that uers?

Can we see your /var/log/XFree86.0.log when you start X as root and when you start X as a normal user.

I maybe wrong, but I still think that this is a problem of permissions on the DRI.

Sorry for taking so long to reply, but in the meanwhile I managed to get an nvidia riva tnt2 32mb card and after that, now I am able to play chromium as non-root without any problems [I made no changes, except removing dri loading from my XF86Config].

With the SiS card, X reported an error with agpart. My kernel log said that agpart could not find any supported chipsets [VIA chipset].
Another thing: My SiS card is PCI. This is because unfortunately I don't have an AGP slot on this motherboard. Would that cause any problems?

If your SIS card is PCI then X will not be able to support it with AGP since
it is not an AGP card. It is a most unhappy state of affairs not to have an
AGP slot on your motherboard which must be very old.

The NVIDIA linux drivers are well supported so that explains why you have no problems using an NVIDIA card.

It is good to hear that you got things working.