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Imre Deak 7d11507605 drm/dp_mst: Fix the DDC I2C device unregistration of an MST port
The WARN below triggers during the removal of an MST port. The problem
is that the parent device's (the connector's kdev) sysfs directory is
removed recursively when the connector is unregistered (even though the
I2C device holds a reference on the parent device). To fix this set
first the Peer Device Type to none which will remove the I2C device.

Note that atm, inconsistently, the parent of the I2C device is initially set to
the DRM kdev and after a Connection Status Notification the parent may be reset
to be the connector's kdev. This problem is addressed by the next patch.

[ 4462.989299] ------------[ cut here ]------------
[ 4463.014940] sysfs group 'power' not found for kobject 'i2c-24'
[ 4463.034664] WARNING: CPU: 0 PID: 970 at fs/sysfs/group.c:281 sysfs_remove_group+0x71/0x80
[ 4463.044357] Modules linked in: snd_hda_intel i915 drm_kms_helper(O) drm netconsole snd_hda_codec_hdmi mei_hdcp x86_pkg_temp_thermal coretemp crct10dif_pclmul snd_intel_dspcf
g crc32_pclmul snd_hda_codec snd_hwdep ghash_clmulni_intel snd_hda_core asix usbnet kvm_intel mii i2c_algo_bit snd_pcm syscopyarea sysfillrect e1000e sysimgblt fb_sys_fops prim
e_numbers ptp pps_core i2c_i801 r8169 mei_me realtek mei [last unloaded: drm]
[ 4463.044399] CPU: 0 PID: 970 Comm: kworker/0:2 Tainted: G           O      5.7.0+ #172
[ 4463.044402] Hardware name: Intel Corporation Tiger Lake Client Platform/TigerLake U DDR4 SODIMM RVP
[ 4463.044423] Workqueue: events drm_dp_delayed_destroy_work [drm_kms_helper]
[ 4463.044428] RIP: 0010:sysfs_remove_group+0x71/0x80
[ 4463.044431] Code: 48 89 df 5b 5d 41 5c e9 cd b6 ff ff 48 89 df e8 95 b4 ff ff eb cb 49 8b 14 24 48 8b 75 00 48 c7 c7 20 0f 3f 82 e8 9f c5 d7 ff <0f> 0b 5b 5d 41 5c c3 0f 1f
84 00 00 00 00 00 48 85 f6 74 31 41 54
[ 4463.044433] RSP: 0018:ffffc900018bfbf0 EFLAGS: 00010282
[ 4463.044436] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000001
[ 4463.044439] RDX: 0000000080000001 RSI: ffff88849e828f38 RDI: 00000000ffffffff
[ 4463.052970] [drm:drm_atomic_get_plane_state [drm]] Added [PLANE💯plane 2B] 00000000c2160caa state to 00000000d172564a
[ 4463.070533] RBP: ffffffff820cea20 R08: ffff88847f4b8958 R09: 0000000000000000
[ 4463.070535] R10: 0000000000000000 R11: 0000000000000000 R12: ffff88848a725018
[ 4463.070537] R13: 0000000000000000 R14: ffffffff827090e0 R15: 0000000000000002
[ 4463.070539] FS:  0000000000000000(0000) GS:ffff88849e800000(0000) knlGS:0000000000000000
[ 4463.070541] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 4463.070543] CR2: 00007fdf8a756538 CR3: 0000000489684001 CR4: 0000000000760ef0
[ 4463.070545] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 4463.070547] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[ 4463.070549] PKRU: 55555554
[ 4463.070551] Call Trace:
[ 4463.070560]  device_del+0x84/0x400
[ 4463.070571]  cdev_device_del+0x10/0x30
[ 4463.070578]  put_i2c_dev+0x69/0x80
[ 4463.070584]  i2cdev_detach_adapter+0x2e/0x60
[ 4463.070591]  notifier_call_chain+0x34/0x90
[ 4463.070599]  blocking_notifier_call_chain+0x3f/0x60
[ 4463.070606]  device_del+0x7c/0x400
[ 4463.087817]  ? lockdep_init_map_waits+0x57/0x210
[ 4463.087825]  device_unregister+0x11/0x60
[ 4463.087829]  i2c_del_adapter+0x249/0x310
[ 4463.087846]  drm_dp_port_set_pdt+0x6b/0x2c0 [drm_kms_helper]
[ 4463.087862]  drm_dp_delayed_destroy_work+0x2af/0x350 [drm_kms_helper]
[ 4463.087876]  process_one_work+0x268/0x600
[ 4463.105438]  ? __schedule+0x30c/0x920
[ 4463.105451]  worker_thread+0x37/0x380
[ 4463.105457]  ? process_one_work+0x600/0x600
[ 4463.105462]  kthread+0x140/0x160
[ 4463.105466]  ? kthread_park+0x80/0x80
[ 4463.105474]  ret_from_fork+0x24/0x50

Cc: <stable@vger.kernel.org>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: Stanislav Lisovskiy <stanislav.lisovskiy@intel.com>
Reviewed-by: Lyude Paul <lyude@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200607212522.16935-1-imre.deak@intel.com
2020-06-11 15:35:25 +03:00
arch ARM/fbdev: sa11x0: Switch to use GPIO descriptors 2020-04-17 15:50:11 +02:00
block block-5.7-2020-04-10 2020-04-10 10:06:54 -07:00
certs .gitignore: add SPDX License Identifier 2020-03-25 11:50:48 +01:00
crypto x86: update AS_* macros to binutils >=2.23, supporting ADX and AVX2 2020-04-09 00:12:48 +09:00
Documentation dt-bindings: display: vc4: hdmi: Add missing clock-names property 2020-06-10 11:09:37 +02:00
drivers drm/dp_mst: Fix the DDC I2C device unregistration of an MST port 2020-06-11 15:35:25 +03:00
fs 10 smb fixes most RDMA (smbdirect) related, also add experimental support for swap over SMB3 mounts, and also adds fix which improves performance of signed connections 2020-04-12 09:41:01 -07:00
include drm/i915/dp_mst: Work around out-of-spec adapters filtering short pulses 2020-06-11 15:28:45 +03:00
init Kbuild updates for v5.7 (2nd) 2020-04-11 09:46:12 -07:00
ipc ipc/util.c: sysvipc_find_ipc() should increase position index 2020-04-10 15:36:22 -07:00
kernel Time(keeping) updates: 2020-04-12 10:13:14 -07:00
lib Kbuild updates for v5.7 (2nd) 2020-04-11 09:46:12 -07:00
LICENSES LICENSES: Rename other to deprecated 2019-05-03 06:34:32 -06:00
mm Merge drm/drm-next into drm-misc-next 2020-04-17 08:12:22 +02:00
net Kbuild updates for v5.7 (2nd) 2020-04-11 09:46:12 -07:00
samples samples/hw_breakpoint: drop use of kallsyms_lookup_name() 2020-04-07 10:43:44 -07:00
scripts kbuild: add dummy toolchains to enable all cc-option etc. in Kconfig 2020-04-09 00:13:45 +09:00
security Keyrings fixes 2020-04-04 12:24:47 -07:00
sound sound fixes for 5.7-rc1 2020-04-10 12:27:06 -07:00
tools Kbuild updates for v5.7 (2nd) 2020-04-11 09:46:12 -07:00
usr kbuild: fix comment about missing include guard detection 2020-04-11 12:09:48 +09:00
virt KVM: Pass kvm_init()'s opaque param to additional arch funcs 2020-03-31 10:48:03 -04:00
.clang-format clang-format: Update with the latest for_each macro list 2020-03-06 21:50:05 +01:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore .gitignore: add SPDX License Identifier 2020-03-25 11:50:48 +01:00
.mailmap mailmap: Add Sedat Dilek (replacement for expired email address) 2020-04-11 09:28:34 -07:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: Hand MIPS over to Thomas 2020-02-24 22:43:18 -08:00
Kbuild kbuild: rename hostprogs-y/always to hostprogs/always-y 2020-02-04 01:53:07 +09:00
Kconfig docs: kbuild: convert docs to ReST and rename to *.rst 2019-06-14 14:21:21 -06:00
MAINTAINERS dt-bindings: display: Convert VC4 bindings to schemas 2020-06-10 11:09:37 +02:00
Makefile Linux 5.7-rc1 2020-04-12 12:35:55 -07:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.