1 This is a historical discription of what is now the kgsl backend 2 in libdrm freedreno (before the upstream drm/msm driver). Note 3 that the kgsl backend requires the "kgsl-drm" shim driver, which 4 usually is in disrepair (QCOM does not build it for android), and 5 due to random differences between different downstream android 6 kernel branches it may or may not work. So YMMV. 7 8 Original README: 9 ---------------- 10 11 Note that current msm kernel driver is a bit strange. It provides a 12 DRM interface for GEM, which is basically sufficient to have DRI2 13 working. But it does not provide KMS. And interface to 2d and 3d 14 cores is via different other devices (/dev/kgsl-*). This is not 15 quite how I'd write a DRM driver, but at this stage it is useful for 16 xf86-video-freedreno and fdre (and eventual gallium driver) to be 17 able to work on existing kernel driver from QCOM, to allow to 18 capture cmdstream dumps from the binary blob drivers without having 19 to reboot. So libdrm_freedreno attempts to hide most of the crazy. 20 The intention is that when there is a proper kernel driver, it will 21 be mostly just changes in libdrm_freedreno to adapt the gallium 22 driver and xf86-video-freedreno (ignoring the fbdev->KMS changes). 23 24 So don't look at freedreno as an example of how to write a libdrm 25 module or a DRM driver.. it is just an attempt to paper over a non- 26 standard kernel driver architecture. 27
