From: David Herrmann Date: Tue, 17 Sep 2013 15:39:54 +0000 (+0200) Subject: logind: listen actively for session devices X-Git-Tag: v208~116 X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?a=commitdiff_plain;ds=sidebyside;h=718d006a63f773c42106494e823250c48942cf08;hp=718d006a63f773c42106494e823250c48942cf08;p=elogind.git logind: listen actively for session devices Session compositors need access to fbdev, DRM and evdev devices if they control a session. To make logind pass them to sessions, we need to listen for them actively. However, we avoid creating new seats for non master-of-seat devices. Only once a seat is created, we start remembering all other session devices. If the last master-device is removed (even if there are other non-master devices still available), we destroy the seat. This is the current behavior, but we need to explicitly implement it now as there may be non-master devices in the seat->devices list. Unlike master devices, we don't care whether our list of non-master devices is complete. We don't export this list but use it only as cache if sessions request these devices. Hence, if a session requests a device that is not in the list, we will simply look it up. However, once a session requested a device, we must be notified of "remove" udev events. So we must link the devices somehow into the device-list. Regarding the implementation, we now sort the device list by the "master" flag. This guarantees that master devices are at the front and non-master devices at the tail of the list. Thus, we can easily test whether a seat has a master device attached. ---