Issue

• After upgrading to kernel 3.10.0-229.el7 from 3.10.0-123.el7, plugging in a mini display port cable to Lenovo thinkpad causes graphical display / Xorg to freeze
• The following backtrace is seen in abrt kernel log / dmesg

WARNING: at drivers/gpu/drm/drm_dp_mst_topology.c:1272 process_single_tx_qlock+0x4b6/0x540 [drm_kms_helper]()
fail
Modules linked in: i915 crct10dif_pclmul crct10dif_common crc32_pclmul crc32c_intel i2c_algo_bit drm_kms_helper ghash_clmulni_intel ahci aesni_intel drm libahci glue_helper e1000e lrw libata gf128mul ablk_helper cryptd ptp pps_core i2c_core video dm_mirror dm_region_hash dm_log dm_mod
CPU: 0 PID: 188 Comm: kworker/0:3 Not tainted 3.10.0-267.el7.x86_64 #1
Hardware name: LENOVO 20EGS0R600/20EGS0R600, BIOS GNET71WW (2.19 ) 02/05/2015
Workqueue: events_long drm_dp_mst_link_probe_work [drm_kms_helper]
 ffff8804638bf8c8 000000002a9533a0 ffff8804638bf880 ffffffff8161eb7e
 ffff8804638bf8b8 ffffffff81071540 000000000000000c 0000000000001000
 000000000000000c 0000000000000000 ffff880463d35618 ffff8804638bf920
Call Trace:
 [<ffffffff8161eb7e>] dump_stack+0x19/0x1b
 [<ffffffff81071540>] warn_slowpath_common+0x70/0xb0
 [<ffffffff810715dc>] warn_slowpath_fmt+0x5c/0x80
 [<ffffffffa019f206>] process_single_tx_qlock+0x4b6/0x540 [drm_kms_helper]
 [<ffffffff810a4be8>] ? __wake_up_common+0x58/0x90
 [<ffffffffa019f2e0>] process_single_down_tx_qlock+0x50/0x110 [drm_kms_helper]
 [<ffffffffa019f3ee>] drm_dp_queue_down_tx+0x4e/0x60 [drm_kms_helper]
 [<ffffffffa01a2728>] drm_dp_mst_i2c_xfer+0x198/0x220 [drm_kms_helper]
 [<ffffffff81270150>] ? TSS_checkhmac2.constprop.6+0x2a0/0x320
 [<ffffffff8127d910>] ? inode_doinit_with_dentry+0x210/0x680
 [<ffffffff811b4655>] ? kmem_cache_alloc+0x35/0x1d0
 [<ffffffffa00561fc>] __i2c_transfer+0x5c/0x70 [i2c_core]
 [<ffffffffa0056c2c>] i2c_transfer+0x5c/0xc0 [i2c_core]
 [<ffffffffa0127c95>] drm_do_probe_ddc_edid+0xe5/0x160 [drm]
 [<ffffffffa012941e>] drm_get_edid+0x3e/0x410 [drm]
 [<ffffffffa01a2449>] drm_dp_add_port+0x399/0x420 [drm_kms_helper]
 [<ffffffff81080038>] ? ptrace_traceme+0x68/0x80
 [<ffffffff81621d3d>] ? schedule_timeout+0x17d/0x2d0
 [<ffffffff81082470>] ? internal_add_timer+0x70/0x70
 [<ffffffff8109c506>] ? finish_wait+0x56/0x70
 [<ffffffff81622312>] ? mutex_lock+0x12/0x2f
 [<ffffffffa019e4ce>] ? drm_dp_mst_wait_tx_reply+0xfe/0x1f0 [drm_kms_helper]
 [<ffffffff8109c680>] ? wake_up_atomic_t+0x30/0x30
 [<ffffffffa01a1f7c>] drm_dp_send_link_address+0xdc/0x210 [drm_kms_helper]
 [<ffffffff810135c6>] ? __switch_to+0x136/0x4a0
 [<ffffffffa01a255d>] drm_dp_check_and_send_link_address+0x8d/0xa0 [drm_kms_helper]
 [<ffffffffa01a258c>] drm_dp_mst_link_probe_work+0x1c/0x20 [drm_kms_helper]
 [<ffffffff810933fb>] process_one_work+0x17b/0x470
 [<ffffffff810941cb>] worker_thread+0x11b/0x400
 [<ffffffff810940b0>] ? rescuer_thread+0x400/0x400
 [<ffffffff8109b68f>] kthread+0xcf/0xe0
 [<ffffffff8109b5c0>] ? kthread_create_on_node+0x140/0x140
 [<ffffffff8162f018>] ret_from_fork+0x58/0x90
 [<ffffffff8109b5c0>] ? kthread_create_on_node+0x140/0x140