1config DRM_RADEON_KMS 2 bool "Enable modesetting on radeon by default" 3 depends on DRM_RADEON 4 select DRM_KMS_HELPER 5 select DRM_TTM 6 help 7 Choose this option if you want kernel modesetting enabled by default, 8 and you have a new enough userspace to support this. Running old 9 userspaces with this enabled will cause pain. 10 11 When kernel modesetting is enabled the IOCTL of radeon/drm 12 driver are considered as invalid and an error message is printed 13 in the log and they return failure. 14 15 KMS enabled userspace will use new API to talk with the radeon/drm 16 driver. The new API provide functions to create/destroy/share/mmap 17 buffer object which are then managed by the kernel memory manager 18 (here TTM). In order to submit command to the GPU the userspace 19 provide a buffer holding the command stream, along this buffer 20 userspace have to provide a list of buffer object used by the 21 command stream. The kernel radeon driver will then place buffer 22 in GPU accessible memory and will update command stream to reflect 23 the position of the different buffers. 24 25 The kernel will also perform security check on command stream 26 provided by the user, we want to catch and forbid any illegal use 27 of the GPU such as DMA into random system memory or into memory 28 not owned by the process supplying the command stream. This part 29 of the code is still incomplete and this why we propose that patch 30 as a staging driver addition, future security might forbid current 31 experimental userspace to run. 32 33 This code support the following hardware : R1XX,R2XX,R3XX,R4XX,R5XX 34 (radeon up to X1950). Works is underway to provide support for R6XX, 35 R7XX and newer hardware (radeon from HD2XXX to HD4XXX). 36