i810 missing GLX_EXT_texture_from_pixmap (affects Xgl)

[Ariel Vardi]

I've managed to install Xgl and compiz on my Vaio SZ 110. It has a Intel 945GM chipset. X uses the i915 driver and OpenGL stuff runs pretty smooth on the regular X server.

But using Xgl the scrolling is extremely slow on firefox for instance. The wobbling effect is also very sluggish. The 'expose', rotations of the cube and some other effects are on the other hand very smooth.

I think i read somewhere that the i915 driver wasn't completely implemented yet and was missing some features that could lead to such poor performance. Is it true?

[Sitsofe Wheeler (sitsofe)]

Yes it is true. For fastest performance a driver has to implement GLX_EXT_texture_from_pixmap (I may have the exact name of the extension wrong) otherwise this rather critical feature will have to be emulated in software. Apparently one of the Intel drivers has other deficiencies too - see http://en.opensuse.org/index.php?title=Xgl_Troubleshooting&oldid=16266#Intel_.2F_open_source_driver_.22i810.22

Xgl is so new and requires such cutting edge features that problems like these are to be expected.

(This bug should thus not be filed against xgl but instead against the xorg drivers for your card. I don't know what drivers you are using but the right thing might be xserver-xorg-driver-i810 ).

[Paul Sladen (sladen)]

If patches become available they can be back-ported, but probably not in the Dapper timeframe.

Xgl is unstable crack, if it becomes more mainstream it's certainly something that can be focused on. Although it's a bit ironic and to make to work it effectively requires extra extensions and the drivers patching...