After updating the kernel (including kernel, kernel-devel, kernel-firmware, kernel-headers) to 2.6.32-642.el6.x86_64, I get a crash on reboot with the messages:

Jun 30 11:32:40 praline kernel: ------------[ cut here ]------------
Jun 30 11:32:40 praline kernel: WARNING: at drivers/gpu/drm/i915/intel_uncore.c:619 hsw_unclaimed_reg_debug+0x80/0xa0 [i915]() (Not tainted)
Jun 30 11:32:40 praline kernel: Hardware name: System Product Name
Jun 30 11:32:40 praline kernel: Unclaimed register detected before writing to register 0x44404
Jun 30 11:32:40 praline kernel: Modules linked in: iptable_filter ip_tables nfsd exportfs autofs4 coretemp nfs lockd fscache auth_rpcgss nfs_acl sunrpc cpufreq_ondemand acpi_cpufreq freq_table mperf ipv6 ppdev raid1 parport_pc parport sg microcode serio_raw snd_hda_codec_hdmi e1000e ptp snd_hda_codec_realtek pps_core snd_hda_codec_generic i2c_i801 snd_hda_intel snd_hda_codec snd_hwdep snd_seq snd_seq_device snd_pcm snd_timer snd soundcore snd_page_alloc shpchp ext4 jbd2 mbcache wmi sr_mod cdrom sd_mod crc_t10dif ahci xhci_hcd i915 drm_kms_helper drm i2c_algo_bit i2c_core video output dm_mirror dm_region_hash dm_log dm_mod [last unloaded: scsi_wait_scan]
Jun 30 11:32:40 praline kernel: Pid: 3232, comm: Xorg Not tainted 2.6.32-642.el6.x86_64 #1
Jun 30 11:32:40 praline kernel: Call Trace:
Jun 30 11:32:40 praline kernel: [<ffffffff8107c911>] ? warn_slowpath_common+0x91/0xe0
Jun 30 11:32:40 praline kernel: [<ffffffff8107ca16>] ? warn_slowpath_fmt+0x46/0x60
Jun 30 11:32:40 praline kernel: [<ffffffffa0169f60>] ? hsw_unclaimed_reg_debug+0x80/0xa0 [i915]
Jun 30 11:32:40 praline kernel: [<ffffffffa016e3c7>] ? gen9_write32+0x57/0x2e0 [i915]
Jun 30 11:32:40 praline kernel: [<ffffffffa014a3a6>] ? i915_gem_object_do_pin+0x416/0x9d0 [i915]
Jun 30 11:32:40 praline kernel: [<ffffffffa010c5bc>] ? gen8_enable_vblank+0x6c/0xa0 [i915]
Jun 30 11:32:40 praline kernel: [<ffffffffa006513d>] ? drm_vblank_enable+0x9d/0x100 [drm]
Jun 30 11:32:40 praline kernel: [<ffffffffa00653b8>] ? drm_vblank_get+0xc8/0xf0 [drm]
Jun 30 11:32:40 praline kernel: [<ffffffffa00654e0>] ? drm_crtc_vblank_get+0x20/0x30 [drm]
Jun 30 11:32:40 praline kernel: [<ffffffffa01a231d>] ? intel_pipe_update_start+0x11d/0x2b0 [i915]
Jun 30 11:32:40 praline kernel: [<ffffffff810a6ac0>] ? autoremove_wake_function+0x0/0x40
Jun 30 11:32:40 praline kernel: [<ffffffffa01872e6>] ? intel_begin_crtc_commit+0x116/0x2c0 [i915]
Jun 30 11:32:40 praline kernel: [<ffffffffa00e4fb9>] ? drm_atomic_helper_commit_planes_on_crtc+0x59/0x240 [drm_kms_helper]
Jun 30 11:32:40 praline kernel: [<ffffffffa018f628>] ? intel_pre_plane_update+0x158/0x160 [i915]
Jun 30 11:32:40 praline kernel: [<ffffffffa018fbc6>] ? intel_atomic_commit+0x596/0x1530 [i915]
Jun 30 11:32:40 praline kernel: [<ffffffffa007eb6f>] ? drm_atomic_check_only+0x37f/0x620 [drm]
Jun 30 11:32:40 praline kernel: [<ffffffffa007eec1>] ? drm_atomic_commit+0x41/0x70 [drm]
Jun 30 11:32:40 praline kernel: [<ffffffffa00e63e8>] ? restore_fbdev_mode+0x258/0x280 [drm_kms_helper]
Jun 30 11:32:40 praline kernel: [<ffffffffa00e83b0>] ? drm_fb_helper_restore_fbdev_mode_unlocked+0x50/0x90 [drm_kms_helper]
Jun 30 11:32:40 praline kernel: [<ffffffffa00e8425>] ? drm_fb_helper_set_par+0x35/0x60 [drm_kms_helper]
Jun 30 11:32:40 praline kernel: [<ffffffffa01a48fa>] ? intel_fbdev_set_par+0x1a/0x60 [i915]
Jun 30 11:32:40 praline kernel: [<ffffffff812e00e2>] ? fb_set_var+0x172/0x380
Jun 30 11:32:40 praline kernel: [<ffffffff811513fe>] ? __dec_zone_page_state+0x2e/0x30
Jun 30 11:32:40 praline kernel: [<ffffffff810a6947>] ? bit_waitqueue+0x17/0xd0
Jun 30 11:32:40 praline kernel: [<ffffffff8112e41e>] ? find_get_page+0x1e/0xa0
Jun 30 11:32:40 praline kernel: [<ffffffff8112f903>] ? filemap_fault+0xd3/0x500
Jun 30 11:32:40 praline kernel: [<ffffffff8118c7f7>] ? mem_cgroup_update_file_mapped+0x17/0x90
Jun 30 11:32:40 praline kernel: [<ffffffff812eed74>] ? fbcon_blank+0x1d4/0x2c0
Jun 30 11:32:40 praline kernel: [<ffffffff81357b46>] ? do_unblank_screen+0xb6/0x1c0
Jun 30 11:32:40 praline kernel: [<ffffffff8134eb01>] ? vt_ioctl+0x1881/0x1af0
Jun 30 11:32:40 praline kernel: [<ffffffffa02739da>] ? jbd2_journal_stop+0x17a/0x2c0 [jbd2]
Jun 30 11:32:40 praline kernel: [<ffffffff8115a629>] ? handle_mm_fault+0x299/0x3d0
Jun 30 11:32:40 praline kernel: [<ffffffff81343342>] ? tty_ioctl+0xa2/0x950
Jun 30 11:32:40 praline kernel: [<ffffffff811af742>] ? vfs_ioctl+0x22/0xa0
Jun 30 11:32:40 praline kernel: [<ffffffff811af8e4>] ? do_vfs_ioctl+0x84/0x580
Jun 30 11:32:40 praline kernel: [<ffffffff8119b881>] ? __fput+0x1a1/0x210
Jun 30 11:32:40 praline kernel: [<ffffffff811afe61>] ? sys_ioctl+0x81/0xa0
Jun 30 11:32:40 praline kernel: [<ffffffff8100b0d2>] ? system_call_fastpath+0x16/0x1b
Jun 30 11:32:40 praline kernel: ---[ end trace bb36c54a01ff63de ]---


For now I have gone back to the previous version of the kernel, but any idea what is causing the problem?

Thanks,

Marian Szebenyi
MacCHESS