1*7688df22SAndroid Build Coastguard WorkerThis is a historical description of what is now the kgsl backend 2*7688df22SAndroid Build Coastguard Workerin libdrm freedreno (before the upstream drm/msm driver). Note 3*7688df22SAndroid Build Coastguard Workerthat the kgsl backend requires the "kgsl-drm" shim driver, which 4*7688df22SAndroid Build Coastguard Workerusually is in disrepair (QCOM does not build it for android), and 5*7688df22SAndroid Build Coastguard Workerdue to random differences between different downstream android 6*7688df22SAndroid Build Coastguard Workerkernel branches it may or may not work. So YMMV. 7*7688df22SAndroid Build Coastguard Worker 8*7688df22SAndroid Build Coastguard WorkerOriginal README: 9*7688df22SAndroid Build Coastguard Worker---------------- 10*7688df22SAndroid Build Coastguard Worker 11*7688df22SAndroid Build Coastguard WorkerNote that current msm kernel driver is a bit strange. It provides a 12*7688df22SAndroid Build Coastguard WorkerDRM interface for GEM, which is basically sufficient to have DRI2 13*7688df22SAndroid Build Coastguard Workerworking. But it does not provide KMS. And interface to 2d and 3d 14*7688df22SAndroid Build Coastguard Workercores is via different other devices (/dev/kgsl-*). This is not 15*7688df22SAndroid Build Coastguard Workerquite how I'd write a DRM driver, but at this stage it is useful for 16*7688df22SAndroid Build Coastguard Workerxf86-video-freedreno and fdre (and eventual gallium driver) to be 17*7688df22SAndroid Build Coastguard Workerable to work on existing kernel driver from QCOM, to allow to 18*7688df22SAndroid Build Coastguard Workercapture cmdstream dumps from the binary blob drivers without having 19*7688df22SAndroid Build Coastguard Workerto reboot. So libdrm_freedreno attempts to hide most of the crazy. 20*7688df22SAndroid Build Coastguard WorkerThe intention is that when there is a proper kernel driver, it will 21*7688df22SAndroid Build Coastguard Workerbe mostly just changes in libdrm_freedreno to adapt the gallium 22*7688df22SAndroid Build Coastguard Workerdriver and xf86-video-freedreno (ignoring the fbdev->KMS changes). 23*7688df22SAndroid Build Coastguard Worker 24*7688df22SAndroid Build Coastguard WorkerSo don't look at freedreno as an example of how to write a libdrm 25*7688df22SAndroid Build Coastguard Workermodule or a DRM driver.. it is just an attempt to paper over a non- 26*7688df22SAndroid Build Coastguard Workerstandard kernel driver architecture. 27