Xorg doesn't work anymore after the latest DRM updates

[Christian Zigotzky <chzigotzky@xenosoft.de>]

Hi All,

Xorg doesn't work anymore after the latest DRM updates. [1]

Error messages:

Jul 03 08:54:51 Fienix systemd[1]: Starting Light Display Manager...
Jul 03 08:54:51 Fienix systemd[1]: Started Light Display Manager.
Jul 03 08:54:51 Fienix kernel: BUG: Kernel NULL pointer dereference on 
read at 0x00000010
Jul 03 08:54:51 Fienix kernel: Faulting instruction address: 
0xc000000000630750
Jul 03 08:54:51 Fienix kernel: Oops: Kernel access of bad area, sig: 11 [#1]
Jul 03 08:54:51 Fienix kernel: BE PAGE_SIZE=4K PREEMPT SMP NR_CPUS=4 
CoreNet Generic
Jul 03 08:54:51 Fienix kernel: Modules linked in: algif_skcipher bnep 
tuner_simple tuner_types tea5767 tuner tda7432 tvaudio msp3400 bttv 
tea575x tveeprom videobuf_dma_sg videobuf_core rc_core videodev mc btusb 
btrtl btbcm btintel bluetooth ecdh_generic ecc uio_pdrv_genirq uio
Jul 03 08:54:51 Fienix kernel: CPU: 3 PID: 4300 Comm: Xorg.wrap Not 
tainted 5.14.0-a3_A-EON_X5000-07637-g3dbdb38e2869-dirty #1
Jul 03 08:54:51 Fienix kernel: NIP:  c000000000630750 LR: 
c00000000060fedc CTR: c000000000630728
Jul 03 08:54:51 Fienix kernel: REGS: c00000008d903470 TRAP: 0300 Not 
tainted  (5.14.0-a3_A-EON_X5000-07637-g3dbdb38e2869-dirty)
Jul 03 08:54:51 Fienix kernel: MSR:  0000000080029002 <CE,EE,ME>  CR: 
20000222  XER: 20000000
Jul 03 08:54:51 Fienix kernel: DEAR: 0000000000000010 ESR: 
0000000000000000 IRQMASK: 0
                                GPR00: c00000000060fedc c00000008d903710 
c00000000190c400 c000000085d59c00
                                GPR04: c00000008d9035b8 ffffffffffffffff 
c0000000870a4900 c000000085b62d00
                                GPR08: 000000000000000f 0000000000000000 
c000000000630728 0000000000000003
                                GPR12: 0000000020000222 c00000003fffeac0 
00000000ffe51070 000000000086007c
                                GPR16: 0000000000862820 00000000ffb7ec68 
0000000000000000 00000000ffffffff
                                GPR20: 00000000c04064a0 0000000000450088 
00000000ffca79e4 5deadbeef0000122
                                GPR24: 5deadbeef0000100 0000000000000000 
c0000000876028f0 c000000080bd4000
                                GPR28: c000000087603c48 c000000085d59d78 
c000000085d59c00 c000000085d59c78
Jul 03 08:54:51 Fienix kernel: NIP [c000000000630750] 
.radeon_ttm_bo_destroy+0x28/0xc0
Jul 03 08:54:51 Fienix kernel: LR [c00000000060fedc] .ttm_bo_put+0x2ec/0x344
Jul 03 08:54:51 Fienix kernel: Call Trace:
Jul 03 08:54:51 Fienix kernel: [c00000008d903710] [c00000000060fbe4] 
.ttm_bo_cleanup_memtype_use+0x54/0x60 (unreliable)
Jul 03 08:54:51 Fienix kernel: [c00000008d903790] [c00000000060fedc] 
.ttm_bo_put+0x2ec/0x344
Jul 03 08:54:51 Fienix kernel: [c00000008d903820] [c000000000630b50] 
.radeon_bo_unref+0x28/0x3c
Jul 03 08:54:51 Fienix kernel: [c00000008d9038a0] [c0000000006d1f6c] 
.radeon_vm_fini+0x1b0/0x1b8
Jul 03 08:54:51 Fienix kernel: [c00000008d903940] [c000000000618e38] 
.radeon_driver_postclose_kms+0x128/0x178
Jul 03 08:54:51 Fienix kernel: [c00000008d9039e0] [c0000000005deb14] 
.drm_file_free+0x1d8/0x278
Jul 03 08:54:51 Fienix kernel: [c00000008d903aa0] [c0000000005def00] 
.drm_release+0x64/0xc8
Jul 03 08:54:51 Fienix kernel: [c00000008d903b30] [c00000000017636c] 
.__fput+0x11c/0x25c
Jul 03 08:54:51 Fienix kernel: [c00000008d903bd0] [c00000000008b1e8] 
.task_work_run+0xa4/0xbc
Jul 03 08:54:51 Fienix kernel: [c00000008d903c70] [c000000000004bf4] 
.do_notify_resume+0x144/0x2f0
Jul 03 08:54:51 Fienix kernel: [c00000008d903d70] [c00000000000b380] 
.syscall_exit_prepare+0x110/0x130
Jul 03 08:54:51 Fienix kernel: [c00000008d903e10] [c000000000000688] 
system_call_common+0x100/0x1fc
Jul 03 08:54:51 Fienix kernel: --- interrupt: c00 at 0x3f4f58
Jul 03 08:54:51 Fienix kernel: NIP:  00000000003f4f58 LR: 
00000000003f4f2c CTR: 0000000000000000
Jul 03 08:54:51 Fienix kernel: REGS: c00000008d903e80 TRAP: 0c00 Not 
tainted  (5.14.0-a3_A-EON_X5000-07637-g3dbdb38e2869-dirty)
Jul 03 08:54:51 Fienix kernel: MSR:  000000000002d002 <CE,EE,PR,ME>  CR: 
20000420  XER: 00000000
Jul 03 08:54:51 Fienix kernel: IRQMASK: 0
                                GPR00: 0000000000000006 00000000ffca66a0 
00000000f798a310 0000000000000000
                                GPR04: 0000000000000000 0000000000000000 
0000000000000000 0000000000000000
                                GPR08: 0000000000000000 0000000000000000 
0000000000000000 0000000000000000
                                GPR12: 0000000000000000 000000000044fff4 
00000000ffe51070 000000000086007c
                                GPR16: 0000000000862820 00000000ffb7ec68 
0000000000000000 00000000ffffffff
                                GPR20: 00000000c04064a0 0000000000450088 
00000000ffca79e4 00000000004317ac
                                GPR24: 00000000004317b8 00000000ffca66d0 
0000000000000001 00000000ffca673c
                                GPR28: 0000000000000001 0000000000000000 
000000000041cff4 0000000000000003
Jul 03 08:54:51 Fienix kernel: NIP [00000000003f4f58] 0x3f4f58
Jul 03 08:54:51 Fienix kernel: LR [00000000003f4f2c] 0x3f4f2c
Jul 03 08:54:51 Fienix kernel: --- interrupt: c00
Jul 03 08:54:51 Fienix kernel: Instruction dump:
Jul 03 08:54:51 Fienix kernel: 40c2fff4 4e800020 7c0802a6 fbc1fff0 
f8010010 3bc3ff88 fbe1fff8 38a0ffff
Jul 03 08:54:51 Fienix kernel: f821ff81 7c7f1b78 e9230168 7fc3f378 
<80890010> 4bffff51 e87f0208 38631df8
Jul 03 08:54:51 Fienix kernel: ---[ end trace ddf73d2d70058380 ]---
Jul 03 08:54:51 Fienix kernel:
Jul 03 08:54:51 Fienix systemd[1]: lightdm.service: Main process exited, 
code=exited, status=1/FAILURE
Jul 03 08:54:51 Fienix systemd[1]: lightdm.service: Failed with result 
'exit-code'.
Jul 03 08:54:51 Fienix avahi-daemon[3857]: Registering new address 
record for 2a02:8109:89c0:ebfc:d372:f06c:9247:7d54 on enP4096p4s4.*.
Jul 03 08:54:51 Fienix systemd[1]: lightdm.service: Scheduled restart 
job, restart counter is at 1.
Jul 03 08:54:51 Fienix systemd[1]: Stopped Light Display Manager.

----
Systems: A-EON AmigaOne X1000 and X5000 with Radeon HD6970 graphics 
cards. [2] [3] [4]

The biggest problem is, that I don't have time for bisecting and fixing 
this issue.

Cheers,
Christian

[1] 
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=e058a84bfddc42ba356a2316f2cf1141974625c9
[2] http://wiki.amiga.org/index.php?title=X5000
[3] https://en.wikipedia.org/wiki/AmigaOne_X1000
[4] https://forum.hyperion-entertainment.com/viewtopic.php?f=58&t=4378