On Wed, Jan 30, 2013 at 11:07:16PM +0100, Daniel Vetter wrote: > On Wed, Jan 30, 2013 at 10:52 PM, Russell King <rmk@xxxxxxxxxxxxxxxx> wrote: > > Also adding Greg and Daniel to this as Daniel introduced the lockdep > > checking. > > > > This looks extremely horrid to be to solve - the paths are rather deep > > where the dependency occurs. The two paths between the locks are: > > > > console_lock+0x5c/0x70 > > register_con_driver+0x44/0x150 > > take_over_console+0x24/0x3b4 > > fbcon_takeover+0x70/0xd4 > > fbcon_event_notify+0x7c8/0x818 > > notifier_call_chain+0x4c/0x8c > > __blocking_notifier_call_chain+0x50/0x68 > > blocking_notifier_call_chain+0x20/0x28 > > > > and > > > > __blocking_notifier_call_chain+0x34/0x68 > > blocking_notifier_call_chain+0x20/0x28 > > fb_notifier_call_chain+0x20/0x28 > > fb_blank+0x40/0xac > > fbcon_blank+0x1f4/0x29c > > do_blank_screen+0x1b8/0x270 > > console_callback+0x74/0x138 > > You want Dave Airlie's pile of locking reworks, which fixes all > currently known offenders around console_lock and fb_notifier. Patches > won't go into 3.9 since it took a few rounds until they did not cause > regression by making these deadlocks easier to hit. > > http://cgit.freedesktop.org/~airlied/linux/log/?h=fbcon-locking-fixes > > Long term solution would be to abolish the fb_notifier, at least for > the purpose of linking fbdevs up with the fbcon and just replace those > with direct function calls. But that requires that we no longer allow > fbdev drivers and the fbcon to be loaded in any arbitrary order. Or > just force fbcon to be built-in if enabled, imo the sane choice (no > one's bothering with config_vt=m either, after all). So... what you seem to be telling me is that 3.9 is going to be a release which issues lockdep complaints when the console blanks, and you think that's acceptable? Adding Linus and Andrew so they're aware of this issue... -- Russell King Linux kernel 2.6 ARM Linux - http://www.arm.linux.org.uk/ maintainer of: _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/dri-devel
