On 2018-04-27 00:40, Laurent Pinchart wrote: > Hi Peter, > > Thank you for the patches. > > On Friday, 27 April 2018 01:31:15 EEST Peter Rosin wrote: >> Hi! >> >> It was noted by Russel King [1] that bridges (not using components) >> might disappear unexpectedly if the owner of the bridge was unbound. >> Jyri Sarha had previously noted the same thing with panels [2]. Jyri >> came up with using device links to resolve the panel issue, which >> was also my (independent) reaction to the note from Russel. >> >> This series builds up to the addition of that link in the last >> patch, but in my opinion the other 23 patches do have merit on their >> own. >> >> The last patch needs testing, while the others look trivial. That >> said, I might have missed some subtlety. > > I don't think this is the way to go. We have a real lifetime management > problem with bridges, and device links are just trying to hide the problem > under the carpet. They will further corner us by making a real fix much more > difficult to implement. I'll try to comment further in the next few days on > what I think a better solution would be, but in a nutshell I believe that > drm_bridge objects need to be refcounted, with a .release() operation to free > the bridge resources when the reference count drops to zero. This shouldn't be > difficult to implement and I'm willing to help. Ok, sp 24/24 is dead, and maybe 23/24 too. But how do you feel about dropping .of_node in favour of .owner? That gets rid of ugly #ifdefs... I also have the nagging feeling that .driver_private serves very little real purpose if there is a .owner so that you can do dev_get_drvdata(bridge->owner) for the cases where the container_of macro is not appropriate. Cheers, Peter
