DRI Driver Features: "ATI Mach64 Both PCI and AGP cards are supported. The AGP mode may be set to 1 or 2. The driver supports 16- and 24-bit (32 bpp framebuffer) color depths, but 16-bit depth is recommended for the best performance. The maximum 3D accelerated resolution/mode may be limited by the size of on-card memory (especially for PCI cards). The following OpenGL features are implemented in software: * Accumulation buffer operations * Stencil operations * Blend subtract, min/max and logic op blend modes * glDrawBuffer(GL_FRONT_AND_BACK) * 1D and 3D textures * Texture borders * GL_BLEND texture environment mode * Texture environments which modulate alpha values (At*Af) are fallbacks or non-compliant (e.g. RGBA textures with MODULATE environment may be non-compliant when alpha blending). * Polygon, line and point smoothing (anti-aliasing) or stippling Other limitations: * Mipmaps are not supported. * Fog is disabled if alpha blending is enabled, but hardware accelerated when alpha blending is not enabled. Extensions which might be doable in hardware, but not currently implemented: * GL_EXT_paletted_texture - not sure about this, but the hardware seems to support a 2K texture palette in RGB 565. * GL_ARB_texture_compression - would need an extension to implement 4:1 VQ texture compression supported by the hardware. The following environment variables are available. Most are for debugging purposes only. * LIBGL_PERFORMANCE_BOXES - Display colored boxes to help identify bottlenecks. * MACH64_NO_IRQS - Do not use IRQs. * MACH64_DEBUG - Produces verbose debugging output. Accepts a comma separated list of parameters: 'all' OR 'sync,api,msg,lru,dri,ioctl,prims,count,nowait'. Of these, two affect driver behavior: 'sync' forces an idle wait at the end of each frame (buffer swap), and 'nowait' disables frame-rate throttling."
