>> > >> >> >> It would be nice to find a way to reclaim the console memory for X, >> >> >> but I'm not sure that can be done and still provide a good way to >> >> >> provide oops support. >> >> > >> >> > What do you think the average user will care about more? >> >> > >> >> > * Seeing kernel oops/panic output about once in a lifetime. >> >> > * Being able to start/use X in the first place and enabling it to >> >> > use all of VRAM. >> >> > >> >> > Personally, I've never even seen any kernel oops/panic output despite >> >> > numerous opportunities for that in the couple of months I've been using >> >> > KMS. But I have spent considerable time and effort trying to get rid of >> >> > the pinned fbcon BO. If the oops/panic output is the only thing >> >> > preventing that, maybe that should only be enabled via some module >> >> > option for developers. >> >> >> >> I'm all for it! >> > >> > I'm looking into the details for this. It will require some changes to >> > internal apis to make it to work. >> > >> >> Can't it print the oops on whatever is currently displayed? >> >> It need not be a dedicated buffer as long as there is always some buffer. >> >> But perhaps this is more complex than that. > > Yes it is very complex. Reading the code and drm specs you come to > realize buffer handling is done with GEM, TTM, or for older drivers drm_maps. > Drivers often handle a combine of those, meaning no real wrapper from one > api to another :-( From the code it appears GEM is the main userland interface > when using KMS. Some how TTM is also usable from userland but I never found a > clear example of how that is done. So to the average userland app writer it is > a mystery. As for hardware that has a static front buffer I can see how to > use drm_maps or TTM but I don't see a easy way to map it to the GEM api. > Also their exist ioctl for gem but it appears no one actually uses them > but instead write their own :-( So you can see the confusion here.
Userspace buffer management interfaces are pre-driver, the only requirement if that they have a 32-bit handle to identify buffers uniquely. Pre-KMS drivers don't exist for the purposes of fb interaction, so drm_maps are ignorable from that pov. > Outside of what I described above the drm_framebuffer handling is > a mess. From what I can see with the code you can only create a > drm_framebuffer with the GEM api. With this case the two most important > functions to provide are This isn't correct. You get a drm_file and a handle, the driver then uses these to do whatever it wants to do. This means lookup a GEM object or whatever but there is no reliance on GEM or any other memory manager outside the driver. Again a handle a file priv are in no way GEM specific. > > dev->mode_config.funcs->fb_create(dev, file_priv, r) > > and > > fb->funcs->create_handle(fb, file_priv, &r->handle); > > As you can see if the functions they depend on a handle and a drm_file. To > make it possible to create a framebuffer internally using a common code we > would remove those requirements. We already have an internal framebuffer creation for fbdev, there is an fb_create callback that does this, its not up to dynamic fbdev creation. > This gets me to point of where to go from here. We have two choices. > The first being we could just make the drm_framebuffer code totally gem > dependent thus we could cleanup the drivers code up by moving gem code > there. The second option is to make the drm_framebuffer code agnostic to the > gem > layer. So I have been pondering on how to make the second option work. > There is one thing that all these layers do share in common. That is they > have some sort of drm_hash with a object lookup. Still pondering how that > would be done. I'm not sure either of these makes sense, can you clearly state the goal and maybe we can work out what you need. Dave. ------------------------------------------------------------------------------ Download Intel® Parallel Studio Eval Try the new software tools for yourself. Speed compiling, find bugs proactively, and fine-tune applications for parallel performance. See why Intel Parallel Studio got high marks during beta. http://p.sf.net/sfu/intel-sw-dev -- _______________________________________________ Dri-devel mailing list Dri-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/dri-devel
