1config DRM_RADEON_KMS 2 bool "Enable modesetting on radeon by default - NEW DRIVER" 3 depends on DRM_RADEON 4 help 5 Choose this option if you want kernel modesetting enabled by default. 6 7 This is a completely new driver. It's only part of the existing drm 8 for compatibility reasons. It requires an entirely different graphics 9 stack above it and works very differently from the old drm stack. 10 i.e. don't enable this unless you know what you are doing it may 11 cause issues or bugs compared to the previous userspace driver stack. 12 13 When kernel modesetting is enabled the IOCTL of radeon/drm 14 driver are considered as invalid and an error message is printed 15 in the log and they return failure. 16 17 KMS enabled userspace will use new API to talk with the radeon/drm 18 driver. The new API provide functions to create/destroy/share/mmap 19 buffer object which are then managed by the kernel memory manager 20 (here TTM). In order to submit command to the GPU the userspace 21 provide a buffer holding the command stream, along this buffer 22 userspace have to provide a list of buffer object used by the 23 command stream. The kernel radeon driver will then place buffer 24 in GPU accessible memory and will update command stream to reflect 25 the position of the different buffers. 26 27 The kernel will also perform security check on command stream 28 provided by the user, we want to catch and forbid any illegal use 29 of the GPU such as DMA into random system memory or into memory 30 not owned by the process supplying the command stream. This part 31 of the code is still incomplete and this why we propose that patch 32 as a staging driver addition, future security might forbid current 33 experimental userspace to run. 34 35 This code support the following hardware : R1XX,R2XX,R3XX,R4XX,R5XX 36 (radeon up to X1950). Works is underway to provide support for R6XX, 37 R7XX and newer hardware (radeon from HD2XXX to HD4XXX). 38