On Wed, Jan 24, 2018 at 07:35:45PM +0100, Lukas Wunner wrote: > * Wilfried Klaebe reports a deadlock when launching Xorg because it > opens /dev/vga_arbiter and calls vga_get(), but apple-gmux is holding > a lock on I/O space indefinitely. It looks like apple-gmux' current > behavior is an abuse of the vgaarb API as locks are not meant to be > held for longer periods: > https://bugzilla.kernel.org/show_bug.cgi?id=88861#c11 > https://bugzilla.kernel.org/attachment.cgi?id=217541 I can confirm that every kernel including 4eebd5a4e726 that I tried needed that commit reverted. Currently I run 4.15-rc9 and 4.14.14 (without 4eebd5a4e726, of course). Somewhere inbetween, using "git revert 4eebd5a4e726" started acting up and I needed to work on it manually, but the diff I currently apply is identical to what Lukas submitted. I see warnings about possible circular locking regarding vgasr_mutex, but haven't had a deadlock yet. I'd be happy to provide more information as timely as job and family allow. Best regards, Wilfried
