Greetings,

I got the below dmesg and the first bad commit is

commit e2764a21797682598150002f00ae58271cd875ef Author: Rob Clark rob@ti.com Date: Fri Oct 4 18:07:42 2013 -0400

drm: convert crtc to properties/state (pageflip)

Break the mutable state of a crtc out into a separate structure and use atomic properties mechanism to set crtc attributes. This makes it easier to have some helpers for crtc->set_property() and for checking for invalid params. The idea is that individual drivers can wrap the state struct in their own struct which adds driver specific parameters, for easy build-up of state across multiple set_property() calls and for easy atomic commit or roll- back.

[ 8.465714] [TTM] Zone kernel: Available graphics memory: 85184 kiB [ 8.468118] [TTM] Initializing pool allocator [ 8.470441] BUG: unable to handle kernel NULL pointer dereference at (null) [ 8.474052] IP: [<c1a503e0>] drm_crtc_init+0x20/0x110 [ 8.475963] *pdpt = 0000000000000000 *pde = f000ff53f000ff53 [ 8.478829] Oops: 0002 [#1] DEBUG_PAGEALLOC [ 8.480018] CPU: 0 PID: 1 Comm: swapper Not tainted 3.12.0-rc3-00010-ge2764a2 #52 [ 8.480018] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011 [ 8.480018] task: c0018000 ti: c001a000 task.ti: c001a000 [ 8.480018] EIP: 0060:[<c1a503e0>] EFLAGS: 00010246 CPU: 0 [ 8.480018] EIP is at drm_crtc_init+0x20/0x110 [ 8.480018] EAX: 00000000 EBX: c6970790 ECX: c2a2fe00 EDX: c69cd008 [ 8.480018] ESI: c69cd008 EDI: c69cd018 EBP: c001bd58 ESP: c001bd40 [ 8.480018] DS: 007b ES: 007b FS: 0000 GS: 00e0 SS: 0068 [ 8.480018] CR0: 8005003b CR2: 00000000 CR3: 03d45000 CR4: 000006b0 [ 8.480018] Stack: [ 8.480018] 000005c0 c69cd008 c1a7d8ba c69c5008 c69cd008 c6970790 c001bd78 c1a7d8e5 [ 8.480018] 00000001 c6970790 c69c5008 c6970790 c69c5008 00000000 c001bd9c c1a7c2a5 [ 8.480018] 00000000 c6970adc c6970790 00000000 c6970790 cd4c9420 00000001 c001bddc [ 8.480018] Call Trace: [ 8.480018] [<c1a7d8ba>] ? cirrus_modeset_init+0x7a/0x290 [ 8.480018] [<c1a7d8e5>] cirrus_modeset_init+0xa5/0x290 [ 8.480018] [<c1a7c2a5>] cirrus_driver_load+0xf5/0x190 [ 8.480018] [<c1a47c83>] drm_get_pci_dev+0x203/0x420 [ 8.480018] [<c1a7dc3b>] cirrus_pci_probe+0x11b/0x150 [ 8.480018] [<c186ca59>] pci_device_probe+0x49/0x140 [ 8.480018] [<c1b6c899>] driver_probe_device+0x159/0x3b0 [ 8.480018] [<c1b6cb50>] ? __device_attach+0x60/0x60 [ 8.480018] [<c1b6cbf9>] __driver_attach+0xa9/0x100 [ 8.480018] [<c1b6cb50>] ? __device_attach+0x60/0x60 [ 8.480018] [<c1b6a364>] bus_for_each_dev+0x74/0xc0 [ 8.480018] [<c1b6c66e>] driver_attach+0x1e/0x20 [ 8.480018] [<c1b6cb50>] ? __device_attach+0x60/0x60 [ 8.480018] [<c1b6aff1>] bus_add_driver+0x111/0x400 [ 8.480018] [<c1b6d437>] driver_register+0xd7/0x1a0 [ 8.480018] [<c186c81a>] __pci_register_driver+0x4a/0x50 [ 8.480018] [<c1a47f4a>] drm_pci_init+0xaa/0x130 [ 8.480018] [<c3ca5516>] ? mgag200_init+0x3c/0x3c [ 8.480018] [<c3ca5548>] cirrus_init+0x32/0x3c [ 8.480018] [<c3c3df76>] do_one_initcall+0x93/0x197 [ 8.480018] [<c1822999>] ? strlen+0x9/0x20 [ 8.480018] [<c3c3d621>] ? repair_env_string+0x2a/0x99 [ 8.480018] [<c1082e9c>] ? parse_args+0x33c/0x510 [ 8.480018] [<c10c6b2b>] ? trace_hardirqs_on+0xb/0x10 [ 8.480018] [<c3c3e16c>] kernel_init_freeable+0xf2/0x1d5 [ 8.480018] [<c3c3d5f7>] ? do_early_param+0xb5/0xb5 [ 8.480018] [<c283fa80>] kernel_init+0x10/0x1c0 [ 8.480018] [<c28774db>] ret_from_kernel_thread+0x1b/0x30 [ 8.480018] [<c283fa70>] ? rest_init+0x170/0x170 [ 8.480018] Code: b6 00 00 00 00 8d bf 00 00 00 00 55 89 e5 57 56 53 83 ec 0c e8 32 76 e2 00 89 d6 89 c3 89 06 8d 7e 10 8b 42 78 89 8a 4c 01 00 00 <80> 20 fe 89 d8 e8 e6 b3 ff ff b9 38 ab 2e c4 89 f8 ba 7d 7c 2d [ 8.480018] EIP: [<c1a503e0>] drm_crtc_init+0x20/0x110 SS:ESP 0068:c001bd40 [ 8.480018] CR2: 0000000000000000 [ 8.561397] ---[ end trace 7a515980e3b79f1d ]---

git bisect start e2764a21797682598150002f00ae58271cd875ef 15c03dd4859ab16f9212238f29dd315654aa94f6 -- git bisect good a342a57d8f30a35a7397d4d950b852913270e48b # 17:21 20+ drm: split property values out git bisect good e184cbdf891bcb7e94b4aef45fb009897e3dd014 # 17:23 20+ drm: Allow drm_mode_object_find() to look up an object of any type git bisect good 2efab5f3331dbbf7c62d66811374d7f44a9a0754 # 17:26 20+ drm: convert plane to properties/state git bisect good 2efab5f3331dbbf7c62d66811374d7f44a9a0754 # 17:29 60+ drm: convert plane to properties/state git bisect bad e2764a21797682598150002f00ae58271cd875ef # 17:29 0- drm: convert crtc to properties/state (pageflip) git bisect good ec8720598ab7101ffdcdce4a6bf29c3184011487 # 17:43 60+ Revert "drm: convert crtc to properties/state (pageflip)" git bisect good 7dee8dff47734ee52da2cd8b8ea9736e42c5062f # 17:49 60+ Merge tag 'pm+acpi-3.12-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm git bisect good a0cf1abc25ac197dd97b857c0f6341066a8cb1cf # 18:13 60+ Add linux-next specific files for 20130927

Thanks, Fengguang