Keyboard and mouse not responding after locking

[Juan Andrés Ghigliazza]

In Ubuntu 16.04, after locking my computer, I cannot return to the login screen. There is just a blank screen, and not signal is received from the monitor neither if I press some keys on the keyboard, nor if I move the mouse. This is happening both, when the computers locks automatically, or when I lock it manually with Ctrl+Alt+l.

I know that the computer is still working perfectly because when this happens, I can make a ssh from other hosts, and can login and do anything. If I restart lightdm service remotely (from the ssh session), I can use it locally again.

I think that the problem could be related to my video driver (my card is "01:00.0 VGA compatible controller: Advanced Micro Devices, Inc. [AMD/ATI] RV516 [Radeon X1300/X1550 Series]"), because I have tried in others computers, and I cannot reproduce the problem.

Thanks very much

[Steve Langasek (vorlon)]

Certainly not a bug in pam. Assuming you're using the Ubuntu desktop rather than another flavor, reassigning this to unity.

[Andrea Azzarone (azzar1)]

Can you reproduce it all times?

[Juan Andrés Ghigliazza (tizone)]

Steve, it was a mistake marking it as a bug in pam.

Andrea, yes I can reproduce it all the times.

[Juan Andrés Ghigliazza (tizone)]

I've seen that the status of this bug is "incomplete". What other info is needed?.

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[tiziano (cucinieri)]

Same issue ...
When happens dmesg results are below ...

[ 838.102411] irq 16: nobody cared (try booting with the "irqpoll" option)
[ 838.102418] CPU: 3 PID: 0 Comm: swapper/3 Not tainted 4.4.0-45-generic #66-Ubuntu
[ 838.102421] Hardware name: /DQ45CB, BIOS CBQ4510H.86A.0133.2011.0810.1010 08/10/2011
[ 838.102423] 0000000000200086 816a872290fe3941 ffff88012bd83e60 ffffffff813f1fe3
[ 838.102427] ffff8800c5952600 ffff8800c59526b4 ffff88012bd83e88 ffffffff810dd7a3
[ 838.102430] ffff8800c5952600 0000000000000000 0000000000000010 ffff88012bd83ec0
[ 838.102433] Call Trace:
[ 838.102435] <IRQ> [<ffffffff813f1fe3>] dump_stack+0x63/0x90
[ 838.102446] [<ffffffff810dd7a3>] __report_bad_irq+0x33/0xc0
[ 838.102449] [<ffffffff810ddb37>] note_interrupt+0x247/0x290
[ 838.102452] [<ffffffff810dadc7>] handle_irq_event_percpu+0x167/0x1d0
[ 838.102455] [<ffffffff810dae6e>] handle_irq_event+0x3e/0x60
[ 838.102457] [<ffffffff810de0a6>] handle_fasteoi_irq+0x96/0x150
[ 838.102461] [<ffffffff810310fa>] handle_irq+0x1a/0x30
[ 838.102465] [<ffffffff8183429b>] do_IRQ+0x4b/0xd0
[ 838.102469] [<ffffffff81832382>] common_interrupt+0x82/0x82
[ 838.102470] <EOI> [<ffffffff816c4dce>] ? cpuidle_enter_state+0x10e/0x2b0
[ 838.102477] [<ffffffff816c4fa7>] cpuidle_enter+0x17/0x20
[ 838.102481] [<ffffffff810c4112>] call_cpuidle+0x32/0x60
[ 838.102483] [<ffffffff816c4f83>] ? cpuidle_select+0x13/0x20
[ 838.102486] [<ffffffff810c43d0>] cpu_startup_entry+0x290/0x350
[ 838.102489] [<ffffffff810516e4>] start_secondary+0x154/0x190
[ 838.102491] handlers:
[ 838.102495] [<ffffffff816157a0>] usb_hcd_irq
[ 838.102528] [<ffffffffc022fdb0>] radeon_driver_irq_handler_kms [radeon]
[ 838.102530] Disabling IRQ #16