Without solving this problem, wayland cannot be used after logon, when using dual monitor. The sesssion stops very easy and often. Work is lost; you have to logon again. E.g. the simple switching between 2 overlapping windows causes the end of the session.
I changed src/mesa/drivers/dri/i915/intel_batchbuffer.c to force a coredump in this case. The stacktrace is added to this bug-report. Linenumbers might deviate a little bit because of extra coding of tracing. The deadlock always occurs at cogl_onscreen_swap_buffers calling cogl_flush(), at the first journal-batch-flush for the offscreen-framebuffer. The deadlock disappeared as soon as cogl is compiled with disabled batching! To minimize this disabling of batching, I made a very dirty but working patch, which is attached to this bug. At program clutter_stage_cogl_redraw_view routine paint_stage is called for the "Unclipped stage paint". This call is manipulated to flush immedately the first journal-entry of the default onscreen framebuffer. This is done by misusing and changing program cogl_framebuffer_set_viewport and by changing _cogl_journal_flush. Apparenly this early flushing causes a lock to be set which avoids the deadlock. I do not know how to see which locks are held and by which process, so I cannot solve the root-cause of thhe problem, but I assume some extra lock must be set in this case to avoid deadlock. With this dirty patch combined with other suggested (simple) patches at #1790525, #1795774 and #1795760 wayland can be run without any problems on dual monitor and "old" intel graphic card. It performs better than lightdm, specially if the monitors are positioned aside of each other. ** Attachment added: "dirty_patch.txt" https://bugs.launchpad.net/ubuntu/+source/mesa/+bug/1797882/+attachment/5223253/+files/dirty_patch.txt -- You received this bug notification because you are a member of Ubuntu-X, which is subscribed to mesa in Ubuntu. https://bugs.launchpad.net/bugs/1797882 Title: At dual monitor intel_do_flush_locked failed: Resource deadlock avoided To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/gnome-shell/+bug/1797882/+subscriptions _______________________________________________ Mailing list: https://launchpad.net/~ubuntu-x-swat Post to : ubuntu-x-swat@lists.launchpad.net Unsubscribe : https://launchpad.net/~ubuntu-x-swat More help : https://help.launchpad.net/ListHelp
