Xenial/raspi2 and RaspberryPi3a+: OOPS during boot

[Paolo Pisati]

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[ 4.334281] [drm] Initialized drm 1.1.0 20060810
[ 4.463211] usbcore: registered new interface driver brcmfmac
[ 4.492438] vc4-drm soc:gpu: bound 3f902000.hdmi (ops vc4_hdmi_ops [vc4])
[ 4.492469] vc4_dsi 3f700000.dsi: DSI not set up by firmware.
[ 4.492502] vc4-drm soc:gpu: bound 3f700000.dsi (ops vc4_dsi_ops [vc4])
[ 4.492548] vc4-drm soc:gpu: bound 3f400000.hvs (ops vc4_hvs_ops [vc4])
[ 4.492677] vc4-drm soc:gpu: bound 3f206000.pixelvalve (ops vc4_crtc_ops [vc4])
[ 4.492757] vc4-drm soc:gpu: bound 3f207000.pixelvalve (ops vc4_crtc_ops [vc4])
[ 4.492834] vc4-drm soc:gpu: bound 3f807000.pixelvalve (ops vc4_crtc_ops [vc4])
[ 4.492870] vc4-drm soc:gpu: failed to bind 3fc00000.v3d (ops vc4_v3d_ops [vc4]): -22
[ 4.501101] Unable to handle kernel NULL pointer dereference at virtual address 00000010
[ 4.509408] pgd = 99df0000
[ 4.512171] [00000010] *pgd=00000000
[ 4.515830] Internal error: Oops: 5 [#1] SMP ARM
[ 4.520516] Modules linked in: vc4(+) drm_mipi_dsi brcmfmac drm_kms_helper brcmutil cfg80211 drm sr9700 fb_sys_fops syscopyarea dm9601 sysfillrect sy
simgblt i2c_bcm2708 bcm2835_gpiomem uio_pdrv_genirq uio
[ 4.539021] CPU: 0 PID: 190 Comm: systemd-udevd Not tainted 4.4.0-1101-raspi2 #109~vc4dbg
[ 4.547326] Hardware name: BCM2709
[ 4.550776] task: 9b5c2f40 ti: 99f8c000 task.ti: 99f8c000
[ 4.556292] PC is at vc4_dsi_unbind+0x78/0x164 [vc4]
[ 4.561336] LR is at irq_work_queue+0x14/0x90
[ 4.565756] pc : [<7f4ab878>] lr : [<80228a18>] psr: 60070013
               sp : 99f8db38 ip : 00000007 fp : 99f8db54
[ 4.577413] r10: 80b05a34 r9 : 80e81ff8 r8 : 98d45c00
[ 4.582715] r7 : 024000c0 r6 : 98c7bc10 r5 : 98d45c00 r4 : 00000000
[ 4.589339] r3 : dc8ba6a2 r2 : dc8ba6a2 r1 : 00000000 r0 : 00000014
[ 4.595965] Flags: nZCv IRQs on FIQs on Mode SVC_32 ISA ARM Segment none
[ 4.603207] Control: 10c5383d Table: 19df006a DAC: 00000051
[ 4.609038] Process systemd-udevd (pid: 190, stack limit = 0x99f8c218)
[ 4.615662] Stack: (0x99f8db38 to 0x99f8e000)
[ 4.620083] db20: 99db1280 99db16c0
[ 4.628391] db40: ffffffea 024000c0 99f8db74 99f8db58 805827c0 7f4ab80c 99db18c0 99f8dbb4 [29/415]
[ 4.636699] db60: 99db1280 99db16c0 99f8dbb4 99f8db78 80582b40 8058278c ffffffea ffffffe0
[ 4.645007] db80: 98d45c00 80b05a1c 99f8dbb4 98c7bc10 98d45c00 99db16c0 9b6b6410 00000000
[ 4.653314] dba0: 9b6b6410 00000000 99f8dbdc 99f8dbb8 7f4aabb4 80582984 9aaf44c8 00000007
[ 4.661622] dbc0: 99db16c0 9aaf4490 00000000 9b6b6410 99f8dc04 99f8dbe0 80582c98 7f4aab24
[ 4.669930] dbe0: 99db16c0 00000000 80e4f358 7f4ba450 9b6b6410 9b6b6410 99f8dc2c 99f8dc08
[ 4.678238] dc00: 80582d9c 80582bc8 9b6b5810 7f4c24ec 80e4f698 80e4f698 7f4aa888 9b6b6410
[ 4.686546] dc20: 99f8dc6c 99f8dc30 7f4aad78 80582ce4 80e0354c 7f4ba488 99ca5d90 dc8ba6a2
[ 4.694854] dc40: 00000000 80f265c4 9b6b6410 7f4c2184 fffffdfb 7f4c2184 00000012 7f4c2600
[ 4.703162] dc60: 99f8dc8c 99f8dc70 8058af58 7f4aacb0 80f265c4 9b6b6410 80e82208 00000000
[ 4.711470] dc80: 99f8dcbc 99f8dc90 80588b78 8058af08 99f8dcbc 808988b8 9b6b6410 7f4c2184
[ 4.719778] dca0: 9b6b6444 80588dc0 00000000 98295000 99f8dcdc 99f8dcc0 80588e5c 80588954
[ 4.728086] dcc0: 00000000 7f4c2184 80e0354c 80588dc0 99f8dd0c 99f8dce0 80586770 80588dcc
[ 4.736394] dce0: 99f8dd18 9b49df5c 9b69bc34 dc8ba6a2 7f4c2184 9aaf4500 80e4f698 80e82130
[ 4.744702] dd00: 99f8dd1c 99f8dd10 805882d0 805866f0 99f8dd4c 99f8dd20 80587dd0 805882b0
[ 4.753010] dd20: 7f4bce20 7f4ba470 99f8dd4c 7f4c2184 00000000 7f4c2600 7f4ba470 7f4ba470
[ 4.761317] dd40: 99f8dd64 99f8dd50 80589944 80587bfc 00000007 00000000 99f8dd74 99f8dd68
[ 4.769625] dd60: 8058ae68 805898c8 99f8dd9c 99f8dd78 7f4ca06c 8058ae24 80e0354c 80e07520
[ 4.777933] dd80: 7f4ca000 00000000 80e07520 98295000 99f8de1c 99f8dda0 80101904 7f4ca00c
[ 4.786241] dda0: 80e76dc0 80e76dc0 99f8ddf4 dc8ba6a2 8024fdbc 00006d6f 80288624 99dcce80
[ 4.794549] ddc0: 1ae39000 7f4c260c 80e0354c 8029c948 99f8de1c 99f8dde0 8029c948 80896dc0
[ 4.802857] dde0: 00000001 80288624 00006d6f 98295000 9d1c4000 dc8ba6a2 7f4c2600 99f8df40
[ 4.811165] de00: 98295040 7f4c272c 7f4c260c 80e0354c 99f8de44 99f8de20 80246ee0 80101838
[ 4.819472] de20: 99f8de44 99f8de30 80288720 00000000 99f8df40 7f4c2700 99f8df34 99f8de48
[ 4.827780] de40: 801bbda8 80246e78 ffff8000 00007fff 7f4c2600 801b9248 7f000000 80e0354c
[ 4.836088] de60: 80aba450 80aba408 80905fd4 00000000 7f4c260c 80e035cc 7f4c2710 7f4c3000
[ 4.844395] de80: 99f8dea0 99f8df40 80e0354c 00000000 99c35180 99c35180 99f8df34 99f8dea8
[ 4.852702] dea0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
[ 4.861010] dec0: 00000000 00000000 6e72656b 00006c65 00000000 00000000 00000000 00000000
[ 4.869317] dee0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
[ 4.877624] df00: 00000000 dc8ba6a2 99f8df24 80e0354c 00000000 76eca65c 00000015 80108fe4
[ 4.885932] df20: 99f8c000 00000000 99f8dfa4 99f8df38 801bc1c8 801ba9bc 00000000 99f8df40
[ 4.894240] df40: 9d1c4000 0002e1b4 9d1f1994 9d1f1784 9d1e65b8 0001b000 0001e7d0 00000000
[ 4.902548] df60: 00000000 00000001 00008d84 00000032 00000033 0000002b 0000001f 00000015
[ 4.910856] df80: 00000000 dc8ba6a2 023fd410 00000000 50626300 0000017b 00000000 99f8dfa8
[ 4.919163] dfa0: 80108e20 801bc10c 023fd410 00000000 00000015 76eca65c 00000000 76ecb82c
[ 4.927471] dfc0: 023fd410 00000000 50626300 0000017b 00020000 004a07cc 023fd298 00000000
[ 4.935779] dfe0: 7ee2b938 7ee2b928 76ec48ff 76e16712 60070030 00000015 00000000 00000000
[ 4.944131] [<7f4ab878>] (vc4_dsi_unbind [vc4]) from [<805827c0>] (component_unbind+0x40/0x78)
[ 4.952885] [<805827c0>] (component_unbind) from [<80582b40>] (component_bind_all+0x1c8/0x244)
[ 4.961657] [<80582b40>] (component_bind_all) from [<7f4aabb4>] (vc4_drm_bind+0x9c/0x18c [vc4])
[ 4.970519] [<7f4aabb4>] (vc4_drm_bind [vc4]) from [<80582c98>] (try_to_bring_up_master.part.0+0xdc/0x11c)
[ 4.980329] [<80582c98>] (try_to_bring_up_master.part.0) from [<80582d9c>] (component_master_add_with_match+0xc4/0x138)
[ 4.991306] [<80582d9c>] (component_master_add_with_match) from [<7f4aad78>] (vc4_platform_drm_probe+0xd4/0xfc [vc4])
[ 5.002109] [<7f4aad78>] (vc4_platform_drm_probe [vc4]) from [<8058af58>] (platform_drv_probe+0x5c/0xc0)
[ 5.011745] [<8058af58>] (platform_drv_probe) from [<80588b78>] (driver_probe_device+0x230/0x478)
[ 5.020762] [<80588b78>] (driver_probe_device) from [<80588e5c>] (__driver_attach+0x9c/0xa0)
[ 5.029336] [<80588e5c>] (__driver_attach) from [<80586770>] (bus_for_each_dev+0x8c/0xd0)
[ 5.037647] [<80586770>] (bus_for_each_dev) from [<805882d0>] (driver_attach+0x2c/0x30)
[ 5.045780] [<805882d0>] (driver_attach) from [<80587dd0>] (bus_add_driver+0x1e0/0x278)
[ 5.053915] [<80587dd0>] (bus_add_driver) from [<80589944>] (driver_register+0x88/0x108)
[ 5.062136] [<80589944>] (driver_register) from [<8058ae68>] (__platform_driver_register+0x50/0x58)
[ 5.071350] [<8058ae68>] (__platform_driver_register) from [<7f4ca06c>] (vc4_drm_register+0x6c/0x78 [vc4])
[ 5.081187] [<7f4ca06c>] (vc4_drm_register [vc4]) from [<80101904>] (do_one_initcall+0xd8/0x230)
[ 5.090115] [<80101904>] (do_one_initcall) from [<80246ee0>] (do_init_module+0x74/0x39c)
[ 5.098339] [<80246ee0>] (do_init_module) from [<801bbda8>] (load_module+0x13f8/0x1574)
[ 5.106473] [<801bbda8>] (load_module) from [<801bc1c8>] (SyS_finit_module+0xc8/0xf8)
[ 5.114430] [<801bc1c8>] (SyS_finit_module) from [<80108e20>] (ret_fast_syscall+0x0/0x1c)
[ 5.122739] Code: e59f10f0 e30d0074 e3470f4b eb366bbc (e5945010)
[ 5.128976] ---[ end trace a3b1e5ef83fc7548 ]---
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The reason for the OOPS are obvious: the DSI side of the vc4 driver fail to attach on the RaspberryPi 3A+ borad (still under investigation):

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[ 4.492469] vc4_dsi 3f700000.dsi: DSI not set up by firmware.
...
[ 4.492870] vc4-drm soc:gpu: failed to bind 3fc00000.v3d (ops vc4_v3d_ops [vc4]): -22
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drivers/gpu/drm/vc4/vc4_dsi.c::vc4_dsi_unbind():

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        if (DSI_PORT_READ(CTRL) == 0) {
                dev_info(dev, "DSI not set up by firmware.\n");
                return 0;
        }
...

the DSI_PORT_READ() call fails and immediately return, so it doesn't have a chance to reach the end of vc4_dsi_bind() and register the dsi struct in the driver data:

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dev_set_drvdata(dev, dsi);
...

and since the vc4 has failed to bind, vc4_dsi_unbind() is called to cleanup:

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struct vc4_dsi *dsi = dev_get_drvdata(dev);

vc4_dsi_connector_destroy(dsi->connector);
...

but it extracts the dsi struct from the driver data and then dereference a field, tripping over a NULL ptr and producing the above OOPS.