* Sebastian Reichel <sre@xxxxxxxxxx> [200225 23:03]: > Hi, > > On Tue, Feb 25, 2020 at 07:42:37AM -0800, Tony Lindgren wrote: > > * Sebastian Reichel <sre@xxxxxxxxxx> [200225 02:29]: > > > On Mon, Feb 24, 2020 at 04:10:11PM -0800, Tony Lindgren wrote: > > > > BTW, I think there's also some refcount issue in general where > > > > the omapdrm related modules cannot be unloaded any longer? > > > > > > I wouldn't be too surprised. The dependencies are quite interesting > > > at the moment with omapdss registering omapdrm and then omapdrm > > > registers the drm_device, which references the encoders from > > > omapdss. I think this is something to look at once Laurent's and > > > my branch have been merged to avoid increasing the complexity. > > > Technically it should be possible to link everything into one > > > module. > > > > Well the DSS is really DOSSI for Display Output SubSystem > > Interconnect :) The devices on the interconnect are mostly > > independent and ideally the toplevel dss driver would just > > provide Linux generic resources to dispc and various output > > drivers. So probably not a good idea to try to build it all > > into a single module. > > All the output drivers and dispc are already in a single module: > omapdss.ko. There is omapdss-base.ko, omapdss.ko and omapdrm.ko > module. omapdss-base.ko contains a few helpers, omapdss.ko contains > dispc and all output encoders, omapdrm has the tiler code and > wraps some of the custom DSS APIs to DRM APIs. I think the best > way forward is to eliminate the custom API and use common DRM > APIs directly. Then merge all 3 modules into one module. > > In theory one could add modules for each encoder, but practically > this only increases complexity. DRM cannnot hotplug encoders, so > removing any module results in complete loss of DRM. Also during > probe we need to load all modules, since something might be > connected. So having extra modules is not really useful? Well my main concern here is that we should use generic Linux frameworks between the devices within DSS where possible. I can see a single driver pile of code quickly turn into a spaghetti of internal calls instead.. Also each devices on the DSS interconnect needs to do pm_runtime_get for it's struct device naturally. If you can avoid the issues above, then I have no objections of just having one module. Regards, Tony
