I have laptop with ATI Radeon HD 5600 (and also processor i5 with integrated graphics) and Debian linux 6. When I switch off radeon card (with 'sudo echo OFF > /sys/kernel/debug/vgaswitcheroo/switch'), kernel crashes. So, I had downloaded kernel sourses and tryed to debug it. I found that function evergreen_suspend(..) (in /drivers/gpu/drm/radeon/evergreen.c) was commented in old kernel versions. If it commented (also in new kernels) switching normally works else kernel will crash with segmentation fault, because rdev->r600_blit (<struct radeon_device*> and <struct r600_blit*>) doesn't init (and in documentation I have founded TODOs like 'write r600_blit') and rdev->r600_blit equals NULL. I afraid I can't write r600_blit but I think function evergreen_suspend should be commented as in old versions of kernel. Thanks.
Is this still an issue on a newer kernel?