On Fri, Jan 17, 2014 at 6:21 AM, Akash Hajari <akashhajari@xxxxxxxxx> wrote: > Hi Rob, > > Thanks for your answer and your example > (https://github.com/robclark/kmscube/blob/master/kmscube.c). I > understood standalone KMS without x11 (as written by you @ > http://lists.freedesktop.org/archives/dri-devel/2012-September/027348.html > ). > > But, looking at Linux Graphics stack > (http://en.wikipedia.org/wiki/File:Linux_Graphics_Stack_2013.svg), I > am confused. Does libGL calls always directly calls libDRM and never > to x-server? you have two cases: 1) direct rendering: rendering commands (gl/gles) go directly to hw (via kernel execbuf/pushbuf/submit type ioctl, usually utilizing helpers/wrappers in libdrm_{intel,radeon,nouveau,freedreno,etc}. But presentation commands (egl/glx), ie. swapbuffers, etc, go via the display server (x11, wayland, etc). 2) indirect rendering (gl + glx only), everything goes to xserver In either case, the KMS APIs are used by the display server. Direct vs indirect rendering is only about the rendering part of things. > If so, then how simple gl example ‘drawf.c’ > (http://www.glprogramming.com/red/chapter08.html) using glBitmap() > work well when x11 server running? > > > Also, when switching between multiple windows, x server running in > backgroung, why drm_mode_addfb (DRM_IOCTL_MODE_ADDFB) getting called > many times? > (as I think, fb might have already created for multiple windows.) no, that would be addfb getting called for every page flip. Technically you could just create the fb once and re-use it as you flip back to a previous buffer. But addfb/rmfb is relatively lightweight operation (the fb is just a wrapper for a GEM object, which itself is not re-allocated each frame). BR, -R > Thanks for your patience, Rob. > > Akash Hajari. > > On 1/14/14, Rob Clark <robdclark@xxxxxxxxx> wrote: >> On Tue, Jan 14, 2014 at 5:15 AM, Akash Hajari <akashhajari@xxxxxxxxx> >> wrote: >>> Hi, >>> I am new to DRM & KMS and I had seen your pdf named "why & how to use kms >>> as >>> your user space display api if choice". >>> I have to understand initial mode setting flow of x server. So is it >>> located in /xorg-server/hw/xfree86/modes/ or some where else? >> >> >> currently it is in each different DDX driver (for example, >> xf86-video-intel, xf86-video-modesetting, etc) >> >> Perhaps either tests/modetest/modetest.c (in libdrm tree) or kmscube >> (https://github.com/robclark/kmscube/blob/master/kmscube.c) might be a >> simpler stand-alone example to look at (the former does only modeset, >> the later does modeset + gl) >> >>> And, I don't know use control node. What's use of /dev/dri/control node? >> >> I don't think it is really used for much yet.. but mostly people just >> use drmOpen() in libdrm and it figures out what device file to open. >> >> BR, >> -R >> >>> >>> Akash Hajari. >>> >>> _______________________________________________ >>> dri-devel mailing list >>> dri-devel@xxxxxxxxxxxxxxxxxxxxx >>> http://lists.freedesktop.org/mailman/listinfo/dri-devel >>> >> _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/dri-devel
