I'm systematically triggering this assertion failure with a simple test drawing textured quads using VBOs.

The code looks like:

    glEnable(GL_VERTEX_ARRAY);
    glEnable(GL_TEXTURE_COORD_ARRAY);
    glEnable(tex->target);

    if (quad->vbo == 0) {
        Vertex vertices[4];

        pf_glGenBuffersARB(1, &quad->vbo);
        pf_glBindBufferARB(GL_ARRAY_BUFFER, quad->vbo);

        vertices[0].x = quad->x;
        vertices[0].y = quad->y;
        vertices[0].tex_x = 0.0f;
        vertices[0].tex_y = 0.0f;

        vertices[1].x = quad->x + quad->width;
        vertices[1].y = quad->y;
        vertices[1].tex_x = tex->max_x;
        vertices[1].tex_y = 0.0f;

        vertices[2].x = quad->x + quad->width;
        vertices[2].y = quad->y + quad->height;
        vertices[2].tex_x = tex->max_x;
        vertices[2].tex_y = tex->max_y;

        vertices[3].x = quad->x;
        vertices[3].y = quad->y + quad->height;
        vertices[3].tex_x = 0.0f;
        vertices[3].tex_y = tex->max_y;

        pf_glBufferDataARB(GL_ARRAY_BUFFER,
                           sizeof(vertices),
                           vertices,
                           GL_STATIC_DRAW_ARB);

    } else {
        pf_glBindBufferARB(GL_ARRAY_BUFFER, quad->vbo);
    }

    glBindTexture(tex->target, tex->handle);
    glVertexPointer(2, GL_FLOAT, sizeof(Vertex), (const GLvoid *) 0);
    glTexCoordPointer(2, GL_FLOAT, sizeof(Vertex), (const GLvoid *) (2 * sizeof(GLfloat)));
    glDrawArrays(GL_QUADS, 0, 4);



This is on a debian unstable running the intel 2.6, linux 2.6.28, running UXA and DRI2. mesa is 154a9e5317f890618932cea0129ef887e16baf84.