linux/drivers/gpu/drm/bridge
Marek Szyprowski f25c835815 drm/bridge: analogix_dp: Postpone enabling runtime power management
Enabling runtime power management early in analogix_dp_bind() causes following
kernel NULL pointer dereference:

Unable to handle kernel NULL pointer dereference at virtual address 000007d8
pgd = 28ffa2e4
[000007d8] *pgd=00000000
Internal error: Oops: 5 [#1] PREEMPT SMP ARM
Modules linked in:
CPU: 6 PID: 69 Comm: kworker/6:1 Not tainted 4.16.0-rc1-00062-ge25751974ba8 #3622
Hardware name: SAMSUNG EXYNOS (Flattened Device Tree)
Workqueue: events deferred_probe_work_func
PC is at analogix_dp_resume+0x8/0xc0
LR is at pm_generic_runtime_resume+0x2c/0x38
pc : [<c0531b98>]    lr : [<c0543fec>] psr: a0000113
sp : ee13fbd8  ip : 0000001a  fp : 00000001
r10: ee0eb080  r9 : c0552bd8  r8 : c0fb1d98
r7 : eebb1010  r6 : eeae9808  r5 : 00000000  r4 : d4850415
r3 : ee0ed010  r2 : b2d05e00  r1 : 00000000  r0 : 00000000
Flags: NzCv  IRQs on  FIQs on  Mode SVC_32  ISA ARM Segment none
Control: 10c5387d  Table: 2000406a  DAC: 00000051
Process kworker/6:1 (pid: 69, stack limit = 0x913205b4)
Stack: (0xee13fbd8 to 0xee140000)
...
[<c0531b98>] (analogix_dp_resume) from [<c0543fec>] (pm_generic_runtime_resume+0x2c/0x38)
[<c0543fec>] (pm_generic_runtime_resume) from [<c054ffb4>] (__genpd_runtime_resume+0x2c/0x8c)
[<c054ffb4>] (__genpd_runtime_resume) from [<c0552d24>] (genpd_runtime_resume+0x14c/0x258)
[<c0552d24>] (genpd_runtime_resume) from [<c0547798>] (__rpm_callback+0x134/0x214)
[<c0547798>] (__rpm_callback) from [<c0547898>] (rpm_callback+0x20/0x80)
[<c0547898>] (rpm_callback) from [<c0546ff4>] (rpm_resume+0x3a0/0x734)
[<c0546ff4>] (rpm_resume) from [<c05475ec>] (__pm_runtime_resume+0x64/0x9c)
[<c05475ec>] (__pm_runtime_resume) from [<c053b95c>] (__device_attach+0x8c/0x134)
[<c053b95c>] (__device_attach) from [<c053ad08>] (bus_probe_device+0x88/0x90)
[<c053ad08>] (bus_probe_device) from [<c05390d0>] (device_add+0x3a8/0x580)
[<c05390d0>] (device_add) from [<c06764c4>] (i2c_register_adapter+0xd4/0x3ec)
[<c06764c4>] (i2c_register_adapter) from [<c05321c8>] (analogix_dp_bind+0x2a0/0x410)
[<c05321c8>] (analogix_dp_bind) from [<c0528e90>] (exynos_dp_bind+0x9c/0x12c)
[<c0528e90>] (exynos_dp_bind) from [<c0535bc4>] (component_bind_all+0xfc/0x258)
[<c0535bc4>] (component_bind_all) from [<c0522ee8>] (exynos_drm_bind+0x15c/0x28c)
[<c0522ee8>] (exynos_drm_bind) from [<c0536378>] (try_to_bring_up_master+0x1b8/0x29c)
[<c0536378>] (try_to_bring_up_master) from [<c05364fc>] (component_add+0xa0/0x170)
[<c05364fc>] (component_add) from [<c0528fe4>] (exynos_dp_probe+0x64/0xb8)
[<c0528fe4>] (exynos_dp_probe) from [<c053debc>] (platform_drv_probe+0x50/0xb0)
[<c053debc>] (platform_drv_probe) from [<c053bd18>] (driver_probe_device+0x2b8/0x4a0)
[<c053bd18>] (driver_probe_device) from [<c0539e4c>] (bus_for_each_drv+0x44/0x8c)
[<c0539e4c>] (bus_for_each_drv) from [<c053b970>] (__device_attach+0xa0/0x134)
[<c053b970>] (__device_attach) from [<c053ad08>] (bus_probe_device+0x88/0x90)
[<c053ad08>] (bus_probe_device) from [<c053b258>] (deferred_probe_work_func+0x3c/0x168)
[<c053b258>] (deferred_probe_work_func) from [<c014352c>] (process_one_work+0x1d0/0x7bc)
[<c014352c>] (process_one_work) from [<c0143b84>] (worker_thread+0x34/0x4dc)
[<c0143b84>] (worker_thread) from [<c014a30c>] (kthread+0x128/0x164)
[<c014a30c>] (kthread) from [<c01010b4>] (ret_from_fork+0x14/0x20)
Exception stack(0xee13ffb0 to 0xee13fff8)
ffa0:                                     00000000 00000000 00000000 00000000
ffc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
ffe0: 00000000 00000000 00000000 00000000 00000013 00000000
Code: e2800e37 eafee601 e92d4070 e1a05000 (e59067d8)
---[ end trace bf6046013df7cab2 ]---

This oops happens, because analogix_dp_bind() calls drm_dp_aux_register()
which registers i2c adapter. I2C core tries to runtime get i2c host
device during registration. This ends in analogix_dp_resume(), but dp
context is NULL there. dp context is set in exynos_dp_bind() after
executing analogix_dp_bind(). Fix this issue by postponing enabling runtime
power management after drm_dp_aux_register().

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Tested-by: Heiko Stuebner <heiko@sntech.de>
Reviewed-by: Heiko Stuebner <heiko@sntech.de>

Signed-off-by: Andrzej Hajda <a.hajda@samsung.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180305085741.18896-3-m.szyprowski@samsung.com
2018-03-07 16:17:58 +01:00
..
adv7511 drm/bridge: adv7511/33: Fix adv7511_cec_init() failure handling 2017-11-30 10:37:11 +05:30
analogix drm/bridge: analogix_dp: Postpone enabling runtime power management 2018-03-07 16:17:58 +01:00
synopsys drm: bridge: dw-hdmi: Fix overflow workaround for Amlogic Meson GX SoCs 2018-03-06 11:52:15 +01:00
analogix-anx78xx.c drm/bridge: analogix-anx78xx: Remove duplicate NULL check 2018-01-18 16:24:29 +02:00
analogix-anx78xx.h drm/bridge: Add Analogix anx78xx support 2016-05-12 11:32:14 +02:00
dumb-vga-dac.c drm/bridge: Add timing support to dumb VGA DAC 2018-01-12 14:14:31 +05:30
Kconfig drm/bridge/sii8620: add remote control support 2017-10-11 13:14:25 +02:00
lvds-encoder.c drm/bridge: Fix lvds-encoder since the panel_bridge rework. 2017-11-30 11:03:45 +05:30
Makefile main drm pull request for v4.15 2017-11-15 20:42:10 -08:00
megachips-stdpxxxx-ge-b850v3-fw.c drm: Nuke drm_atomic_helper_connector_dpms 2017-08-08 14:48:48 +02:00
nxp-ptn3460.c drm: Nuke drm_atomic_helper_connector_dpms 2017-08-08 14:48:48 +02:00
panel.c drm/bridge: make drm_panel_bridge_remove more robust 2017-10-10 11:32:35 +02:00
parade-ps8622.c drm: Nuke drm_atomic_helper_connector_dpms 2017-08-08 14:48:48 +02:00
sii902x.c drm: Nuke drm_atomic_helper_connector_dpms 2017-08-08 14:48:48 +02:00
sii9234.c drm/bridge: add Silicon Image SiI9234 driver 2017-10-06 14:28:22 +02:00
sil-sii8620.c drm/edid: Allow HDMI infoframe without VIC or S3D 2017-11-22 19:24:34 +02:00
sil-sii8620.h drm/bridge/sii8620: add HSIC initialization code 2017-02-02 15:15:30 +05:30
tc358767.c Merge tag 'drm-misc-next-2017-11-30' of git://anongit.freedesktop.org/drm/drm-misc into drm-next 2017-12-04 05:42:49 +10:00
ti-tfp410.c drm: Nuke drm_atomic_helper_connector_dpms 2017-08-08 14:48:48 +02:00