| Summary: | [regression] WARNING ... i965_enable_backlight ... backlight already enabled | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Product: | DRI | Reporter: | Manuel Krause <manuelkrause> | ||||||||
| Component: | DRM/Intel | Assignee: | Jani Nikula <jani.nikula> | ||||||||
| Status: | CLOSED FIXED | QA Contact: | Intel GFX Bugs mailing list <intel-gfx-bugs> | ||||||||
| Severity: | normal | ||||||||||
| Priority: | highest | CC: | intel-gfx-bugs, manuelkrause, pedrib, peter.klotz99 | ||||||||
| Version: | unspecified | ||||||||||
| Hardware: | All | ||||||||||
| OS: | Linux (All) | ||||||||||
| Whiteboard: | |||||||||||
| i915 platform: | i915 features: | ||||||||||
| Attachments: |
|
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Created attachment 102287 [details]
MK.backlight-WARN-message.bisect.log
Please, advise me, what additional information I can add, that you may need. This WARNING message and the wrong console backlight issue persists until the actual vanilla kernel 3.15.5. Thank you in advance, Manuel Jani, never trust hardware state after the BIOS touches it... Starting with Linux 3.14 I obtain a backtrace very similar to the one in the original bug comment every time the machine is booted up. The backtrace produced by current kernel 3.15.6: [ 13.813399] ------------[ cut here ]------------ [ 13.813446] WARNING: CPU: 0 PID: 253 at drivers/gpu/drm/i915/intel_panel.c:714 i965_enable_backlight+0x12a/0x150 [i915]() [ 13.813446] backlight already enabled [ 13.813485] Modules linked in: ppdev mousedev joydev uvcvideo videobuf2_vmalloc videobuf2_memops videobuf2_core uas videodev media btusb bluetooth coretemp 6lowpan_iphc hwmon kvm_intel kvm arc4 microcode iwldvm evdev mac80211 mac_hid serio_raw psmouse pcspkr iwlwifi lpc_ich(+) i915(+) snd_hda_codec_hdmi cfg80211 r852 sm_common r592 nand nand_ecc nand_ids mtd memstick snd_hda_codec_realtek snd_hda_codec_generic drm_kms_helper r8169 mii snd_hda_intel snd_hda_controller thermal tpm_tis parport_pc tpm drm parport asus_laptop battery ac snd_hda_codec video sparse_keymap rfkill input_polldev snd_hwdep snd_pcm snd_timer intel_agp shpchp snd acpi_cpufreq intel_gtt i2c_algo_bit i2c_core soundcore button processor fuse vboxnetflt(O) vboxdrv(O) ext4 crc16 mbcache jbd2 sha256_ssse3 sha256_generic ecb cbc algif_skcipher [ 13.813501] af_alg dm_crypt dm_mod sr_mod cdrom sd_mod crct10dif_generic crc_t10dif crct10dif_common hid_generic hid_cherry usbhid hid usb_storage atkbd libps2 sdhci_pci sdhci led_class mmc_core ahci libahci firewire_ohci firewire_core crc_itu_t sata_sil24 libata scsi_mod ehci_pci uhci_hcd ehci_hcd usbcore usb_common i8042 serio [ 13.813504] CPU: 0 PID: 253 Comm: systemd-udevd Tainted: G O 3.15.6-1-ARCH #1 [ 13.813505] Hardware name: ASUSTeK Computer Inc. B50A /B50A , BIOS 212 10/09/2009 [ 13.813508] 0000000000000000 0000000040a78d7d ffff880232f6f250 ffffffff8150848e [ 13.813509] ffff880232f6f298 ffff880232f6f288 ffffffff81069b2d ffff8802337dc000 [ 13.813511] 0000000000000000 ffff880232f3a800 00000000e0000000 ffff8800b92d7e00 [ 13.813511] Call Trace: [ 13.813517] [<ffffffff8150848e>] dump_stack+0x4d/0x6f [ 13.813520] [<ffffffff81069b2d>] warn_slowpath_common+0x7d/0xa0 [ 13.813522] [<ffffffff81069bac>] warn_slowpath_fmt+0x5c/0x80 [ 13.813544] [<ffffffffa06a495b>] ? gen4_read32+0x4b/0xd0 [i915] [ 13.813567] [<ffffffffa06e1cea>] i965_enable_backlight+0x12a/0x150 [i915] [ 13.813591] [<ffffffffa06e2d02>] intel_panel_enable_backlight+0x82/0xe0 [i915] [ 13.813612] [<ffffffffa06a4c40>] ? gen4_write64+0xc0/0xc0 [i915] [ 13.813635] [<ffffffffa06e0a9b>] intel_enable_lvds+0x16b/0x180 [i915] [ 13.813656] [<ffffffffa06a4c40>] ? gen4_write64+0xc0/0xc0 [i915] [ 13.813678] [<ffffffffa06b9319>] i9xx_crtc_enable+0x2e9/0x420 [i915] [ 13.813701] [<ffffffffa06bc03f>] __intel_set_mode+0x7ff/0x16b0 [i915] [ 13.813724] [<ffffffffa06bf686>] intel_set_mode+0x16/0x30 [i915] [ 13.813747] [<ffffffffa06c0740>] intel_crtc_set_config+0xa90/0xde0 [i915] [ 13.813756] [<ffffffffa00dde71>] drm_mode_set_config_internal+0x61/0xf0 [drm] [ 13.813760] [<ffffffffa01d2643>] drm_fb_helper_restore_fbdev_mode+0xb3/0xe0 [drm_kms_helper] [ 13.813763] [<ffffffffa01d4871>] drm_fb_helper_set_par+0x31/0x80 [drm_kms_helper] [ 13.813766] [<ffffffff812f2460>] fbcon_init+0x590/0x610 [ 13.813769] [<ffffffff81369b88>] visual_init+0xb8/0x120 [ 13.813771] [<ffffffff8136c086>] do_bind_con_driver+0x176/0x3f0 [ 13.813773] [<ffffffff8136c894>] do_take_over_console+0xb4/0x1b0 [ 13.813775] [<ffffffff812f2543>] do_fbcon_takeover+0x63/0xd0 [ 13.813776] [<ffffffff812f6bad>] fbcon_event_notify+0x6cd/0x7d0 [ 13.813779] [<ffffffff815117dd>] notifier_call_chain+0x4d/0x70 [ 13.813782] [<ffffffff81091fb7>] __blocking_notifier_call_chain+0x47/0x60 [ 13.813784] [<ffffffff81091fe6>] blocking_notifier_call_chain+0x16/0x20 [ 13.813786] [<ffffffff812fce4b>] fb_notifier_call_chain+0x1b/0x20 [ 13.813787] [<ffffffff812ff03e>] register_framebuffer+0x20e/0x360 [ 13.813791] [<ffffffffa01d465f>] drm_fb_helper_initial_config+0x35f/0x540 [drm_kms_helper] [ 13.813812] [<ffffffffa06a4c8f>] ? gen4_write32+0x4f/0xd0 [i915] [ 13.813840] [<ffffffffa06cb73f>] intel_fbdev_initial_config+0x1f/0x30 [i915] [ 13.813870] [<ffffffffa06ecfa4>] i915_driver_load+0xf74/0xfd0 [i915] [ 13.813873] [<ffffffff81296168>] ? kobject_uevent_env+0x178/0x690 [ 13.813876] [<ffffffff8138d107>] ? get_device+0x17/0x30 [ 13.813878] [<ffffffff81392d55>] ? klist_class_dev_get+0x15/0x20 [ 13.813881] [<ffffffff814fb5c8>] ? klist_node_init+0x38/0x60 [ 13.813883] [<ffffffff814fb686>] ? klist_add_tail+0x46/0x50 [ 13.813884] [<ffffffff8138e9eb>] ? device_add+0x1db/0x6d0 [ 13.813892] [<ffffffffa00db7c7>] ? drm_sysfs_device_add+0xd7/0x120 [drm] [ 13.813898] [<ffffffffa00d7bcd>] drm_dev_register+0xad/0x100 [drm] [ 13.813904] [<ffffffffa00da7a4>] drm_get_pci_dev+0xd4/0x220 [drm] [ 13.813921] [<ffffffffa066960b>] i915_pci_probe+0x3b/0x60 [i915] [ 13.813923] [<ffffffff812ceda5>] local_pci_probe+0x45/0xa0 [ 13.813924] [<ffffffff812ce4e5>] ? pci_match_device+0xc5/0xd0 [ 13.813926] [<ffffffff812cef01>] pci_device_probe+0x101/0x150 [ 13.813929] [<ffffffff81391f23>] driver_probe_device+0xa3/0x410 [ 13.813931] [<ffffffff8139235b>] __driver_attach+0x8b/0x90 [ 13.813933] [<ffffffff813922d0>] ? __device_attach+0x40/0x40 [ 13.813935] [<ffffffff8138fcc3>] bus_for_each_dev+0x73/0xc0 [ 13.813937] [<ffffffff8139195e>] driver_attach+0x1e/0x20 [ 13.813939] [<ffffffff81391510>] bus_add_driver+0x180/0x250 [ 13.813945] [<ffffffffa072d000>] ? 0xffffffffa072cfff [ 13.813947] [<ffffffff81392a44>] driver_register+0x64/0xf0 [ 13.813950] [<ffffffffa072d000>] ? 0xffffffffa072cfff [ 13.813951] [<ffffffff812ce64b>] __pci_register_driver+0x4b/0x50 [ 13.813957] [<ffffffffa00da9fa>] drm_pci_init+0x10a/0x140 [drm] [ 13.813959] [<ffffffff81091fe6>] ? blocking_notifier_call_chain+0x16/0x20 [ 13.813962] [<ffffffffa072d000>] ? 0xffffffffa072cfff [ 13.813981] [<ffffffffa072d06a>] i915_init+0x6a/0x6c [i915] [ 13.813983] [<ffffffff81002162>] do_one_initcall+0xf2/0x1b0 [ 13.813985] [<ffffffff81091fc2>] ? __blocking_notifier_call_chain+0x52/0x60 [ 13.813989] [<ffffffff810e9b0e>] load_module+0x1e0e/0x2580 [ 13.813990] [<ffffffff810e6290>] ? store_uevent+0x70/0x70 [ 13.813993] [<ffffffff810ea34d>] SyS_init_module+0xcd/0x120 [ 13.813996] [<ffffffff81516229>] system_call_fastpath+0x16/0x1b [ 13.813998] ---[ end trace 581ac8a9ff435241 ]--- Does it look like the same underlying problem or should I report another bug? Just a little update about the second issue I've had mixed in here: Either with kernel 3.15.6 and above or with changed code in the Xorg/ Mesa/ drm/ xf86-video-intel .rpm-packages that I update from http://download.opensuse.org/repositories/home:/pontostroy:/X11/openSUSE_13.1/ regularily I can now switch from my KDE desktop to a vt console (and back) after resume from hibernation without loosing the initial screen brightness. So this little part is solved for me, while the backlight-enabled WARNING still remains with 3.15.8. Regards, Manuel Created attachment 104527 [details]
dmesg debug=0xe
I can reproduce this consistently by booting up, hibernating, resuming, hibernating again and resuming again. From the second resume onwards, the bug appears at least at every resume. Please see attached dmesg log with drm.debug=0xe - the bug trace starts at 4274.
I have a Lenovo T400 with GM45 and I'm connecting it to an external monitor via a docking bay and disabling the LVDS screen. I've tried using xrandr to disconnect the external monitor and connect the internal screen but the bug appears to happen anyway.
This happens with 3.14.14 and 3.15.9. It did not happen with the 3.13 series kernels.
Let me know if you need more information.
Similar output after each suspend/resume cycle on Acer C720 and Toshiba CB35. [ 301.551363] ------------[ cut here ]------------ [ 301.551386] WARNING: CPU: 0 PID: 71 at drivers/gpu/drm/i915/intel_panel.c:804 pch_enable_backlight+0x1ba/0x200 [i915]() [ 301.551387] cpu backlight already enabled [ 301.551423] Modules linked in: snd_hda_codec_hdmi tpm_infineon joydev mousedev uas usb_storage coretemp hwmon intel_rapl arc4 x86_pkg_temp_thermal intel_powerclamp ath9k kvm_intel ath9k_common ath9k_hw kvm cyapa ath iTCO_wdt iTCO_vendor_support mac80211 crct10dif_pclmul crc32_pclmul crc32c_intel ghash_clmulni_intel cryptd microcode evdev chromeos_laptop mac_hid cfg80211 serio_raw pcspkr rfkill snd_hda_codec_realtek fan i2c_i801 thermal snd_hda_codec_generic ac i915 battery snd_hda_intel snd_hda_controller tpm_tis tpm snd_hda_codec drm_kms_helper snd_hwdep drm snd_pcm video gpio_lynxpoint snd_timer 8250_dw dw_dmac lpc_ich intel_gtt snd i2c_algo_bit i2c_designware_platform i2c_designware_pci i2c_designware_core soundcore spi_pxa2xx_platform shpchp dw_dmac_pci dw_dmac_core button processor [ 301.551435] ext4 crc16 mbcache jbd2 sd_mod crc_t10dif crct10dif_common atkbd libps2 ahci libahci libata scsi_mod i8042 serio xhci_hcd usbcore usb_common sdhci_acpi sdhci led_class mmc_core [ 301.551439] CPU: 0 PID: 71 Comm: kworker/u4:2 Tainted: G O 3.17.0-rc1 #1 [ 301.551440] Hardware name: Toshiba Leon, BIOS 12/04/2013 [ 301.551445] Workqueue: events_unbound async_run_entry_fn [ 301.551448] 0000000000000000 000000004635ec02 ffff880037dd7970 ffffffff8153db1c [ 301.551450] ffff880037dd79b8 ffff880037dd79a8 ffffffff8106fbdd ffff880037f00000 [ 301.551452] ffff880073c61400 0000000000000003 0000000080000000 ffff880073c16b38 [ 301.551453] Call Trace: [ 301.551459] [<ffffffff8153db1c>] dump_stack+0x4d/0x6f [ 301.551463] [<ffffffff8106fbdd>] warn_slowpath_common+0x7d/0xa0 [ 301.551465] [<ffffffff8106fc5c>] warn_slowpath_fmt+0x5c/0x80 [ 301.551479] [<ffffffffa054ce9a>] pch_enable_backlight+0x1ba/0x200 [i915] [ 301.551490] [<ffffffffa054d604>] intel_panel_enable_backlight+0xa4/0x100 [i915] [ 301.551501] [<ffffffffa053e6a4>] intel_edp_backlight_on+0x54/0x140 [i915] [ 301.551512] [<ffffffffa0536db3>] intel_enable_ddi+0xb3/0x100 [i915] [ 301.551524] [<ffffffffa0521e79>] haswell_crtc_enable+0x599/0xa70 [i915] [ 301.551536] [<ffffffffa04ec357>] ? i915_gem_object_ggtt_unpin+0x47/0x90 [i915] [ 301.551548] [<ffffffffa051c32a>] __intel_set_mode+0x87a/0x16d0 [i915] [ 301.551559] [<ffffffffa03a364e>] ? drm_ut_debug_printk+0x6e/0x90 [drm] [ 301.551571] [<ffffffffa0526b08>] intel_modeset_setup_hw_state+0x878/0xd50 [i915] [ 301.551583] [<ffffffffa0509a10>] ? hsw_write64+0x150/0x150 [i915] [ 301.551590] [<ffffffffa03b905f>] ? drm_modeset_lock+0x2f/0xd0 [drm] [ 301.551596] [<ffffffffa03b9149>] ? drm_modeset_lock_all_crtcs+0x49/0x70 [drm] [ 301.551603] [<ffffffffa04c23a9>] __i915_drm_thaw+0x159/0x1d0 [i915] [ 301.551611] [<ffffffffa04c2cd8>] i915_resume+0x28/0x50 [i915] [ 301.551619] [<ffffffffa04c2d15>] i915_pm_resume+0x15/0x20 [i915] [ 301.551623] [<ffffffff812e93c4>] pci_pm_resume+0x64/0xb0 [ 301.551626] [<ffffffff812e9360>] ? pci_pm_thaw+0xa0/0xa0 [ 301.551630] [<ffffffff813b925c>] dpm_run_callback+0x4c/0x150 [ 301.551633] [<ffffffff813b9e76>] device_resume+0xd6/0x200 [ 301.551636] [<ffffffff813b9fbd>] async_resume+0x1d/0x50 [ 301.551639] [<ffffffff81090267>] async_run_entry_fn+0x37/0x130 [ 301.551642] [<ffffffff81088273>] process_one_work+0x173/0x410 [ 301.551645] [<ffffffff8108881b>] worker_thread+0x6b/0x4a0 [ 301.551647] [<ffffffff810887b0>] ? init_pwq.part.22+0x10/0x10 [ 301.551649] [<ffffffff8108d79a>] kthread+0xea/0x100 [ 301.551652] [<ffffffff8108d6b0>] ? kthread_create_on_node+0x1b0/0x1b0 [ 301.551655] [<ffffffff81543a3c>] ret_from_fork+0x7c/0xb0 [ 301.551657] [<ffffffff8108d6b0>] ? kthread_create_on_node+0x1b0/0x1b0 [ 301.551659] ---[ end trace 649897977063d845 ]--- Manuel, Peter, Pedro, will you confirm that you suffer no degraded functionality coincident with the warning message? Assuming it's just an annoyance, I've proposed a fix at http://lists.freedesktop.org/archives/intel-gfx/2014-August/050976.html. No ill effects that I have noticed, but I can't say I have ran extensive testing. Regards, Pedro Hi Scot The backlight seems to work properly. Regards, Peter. Coincidently with this WARNING there's no negative effect. But it definitely shows, that there's some issue within the initialization of the backlight. On my side, I've found out, that my Comment 5 is not valid. It highly depends on the packages I'd installed -- whether the vt console backlight ever gets the normal value or not or can even keep it after resume from hibernation. Removing this -really annoying- msg may lead you all away from fixing the culprit code... Best regards, Manuel Manuel, like you I would prefer to go to the root of this bug and iron it out. However the only way to do that is to provide information and test cases to the developers. If you have any suggestion fire away. Else they can't really keep guessing, and so far there seem to be no ill effects from this warning. Pedro, please, don't get impolite or trolling. I've provided as much info as possible. If noone asks for more for real debugging... If the underlying BUG isn't fixed, we don't have any effort by removing a kernel WARNING message column by a short debug message. And that's what Scot's patch is all about: That's cosmetics only. Manuel Manuel, I didn't mean to be impolite. I never disagreed that it's just a cosmetic fix. What I meant to say is that I don't have the expertise to find out what's wrong, so if the kernel developer suggests masking it and I can see no ill effects then I will take his suggestion. My question was a honest one: if, unlike me, you have the expertise then please suggest a way forward. If not then we don't really have another chance but following Scot's suggestion? My opinion, again: A cosmetic correction is no fix. So this very bugreport should still remain open unless a real developer - and not a code cosmetician - marks it as really fixed. I'm no developer either, but I feel free to add some more or less useful thoughts, as I follow kernel development for decades now. And, @Pedro, noone would need to propose a way forward together with a bug report at all. BTW, I did the bisect.log from above -- any efforts? Manuel The warning is now silenced by commit 813008cd3e93ea8a571b2b7d5b9360a3105b50f7 Author: Scot Doyle <lkml14@scotdoyle.com> Date: Tue Aug 19 02:07:13 2014 +0000 drm/i915: don't warn if backlight unexpectedly enabled in drm-intel-fixes. Thank you for fixing this bug. Regards Pedro May I ask, in which kernels this underlying issue is fixed, and in which only the kernel WARNING is replaced by something shorter? Thanks, Manuel Krause Upstream v3.17-rc4 and later. Hi Jani, to avoid future duplicate bug reports for years to come, doesn't it make sense to port the patch to -stable (especially longterm 3.14)? Regards, Pedro I would also want to encourage you to bring the patch to earlier kernels! The patch applies and works fine on 3.16.5 (that's what I've tested most recently). Best regards, Manuel I sent a stable backport request to the stable team. Up to them to pick it up. Thanks. |
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Created attachment 102286 [details] dmesg.3.14.10-vanilla.20140704.drm.debug=0xe.log I'm getting this WARNING since 3.14.x after resuming from suspend-to-disk/ hibernate: [30553.549066] ------------[ cut here ]------------ [30553.549104] WARNING: CPU: 0 PID: 13518 at drivers/gpu/drm/i915/intel_panel.c:727 i965_enable_backlight+0x12a/0x150 [i915]() [30553.549105] backlight already enabled [30553.549129] Modules linked in: xts gf128mul dm_crypt pppoe pppox af_packet ppp_generic slhc xt_pkttype xt_LOG xt_limit ip6t_REJECT xt_tcpudp nf_conntrack_ipv6 nf_defrag_ipv6 ip6table_raw ipt_REJECT iptable_raw xt_CT iptable_filter ip6table_mangle pci_stub nf_conntrack_netbios_ns nf_conntrack_broadcast vboxpci(O) nf_conntrack_ipv4 nf_defrag_ipv4 vboxnetadp(O) ip_tables vboxnetflt(O) xt_conntrack nf_conntrack ip6table_filter ip6_tables x_tables vboxdrv(O) fuse hp_wmi sparse_keymap iTCO_wdt rfkill iTCO_vendor_support coretemp kvm_intel kvm snd_hda_codec_hdmi microcode snd_hda_codec_analog snd_hda_codec_generic joydev serio_raw snd_hda_intel snd_hda_codec snd_hwdep snd_pcm snd_seq snd_timer snd_seq_device snd lpc_ich mfd_core tg3 libphy ptp pps_core tpm_infineon soundcore wmi battery tpm_tis tpm hp_accel [30553.549135] lis3lv02d input_polldev evdev ac acpi_cpufreq sg loop dm_mod ipv6 autofs4 btrfs raid6_pq xor i915 drm_kms_helper drm i2c_algo_bit video button [30553.549138] CPU: 0 PID: 13518 Comm: kworker/u8:4 Tainted: G O 3.14.10-ck1-XTRA #14 [30553.549138] Hardware name: Hewlett-Packard HP Compaq 6730b (KU489ET#ABD)/30DD, BIOS 68PDD Ver. F.20 12/07/2011 [30553.549144] Workqueue: events_unbound async_run_entry_fn [30553.549146] 0000000000000009 ffff880127c139f8 ffffffff814a3140 ffff880127c13a40 [30553.549148] ffff880127c13a30 ffffffff810435c3 ffff8800b5798000 0000000000000000 [30553.549149] ffff8800b5791400 00000000e0000000 ffff8800b56e0700 ffff880127c13a90 [30553.549150] Call Trace: [30553.549156] [<ffffffff814a3140>] dump_stack+0x4d/0x6f [30553.549158] [<ffffffff810435c3>] warn_slowpath_common+0x73/0x90 [30553.549160] [<ffffffff81043627>] warn_slowpath_fmt+0x47/0x50 [30553.549178] [<ffffffffa00f038f>] ? gen4_read32+0x2f/0x40 [i915] [30553.549194] [<ffffffffa00d94fa>] i965_enable_backlight+0x12a/0x150 [i915] [30553.549210] [<ffffffffa00da4e4>] intel_panel_enable_backlight+0xa4/0xe0 [i915] [30553.549231] [<ffffffffa00f0460>] ? gen4_write64+0x40/0x40 [i915] [30553.549245] [<ffffffffa00c4ea8>] intel_enable_lvds+0x158/0x170 [i915] [30553.549260] [<ffffffffa00f0460>] ? gen4_write64+0x40/0x40 [i915] [30553.549273] [<ffffffffa00b9cd1>] i9xx_crtc_enable+0x2e1/0x410 [i915] [30553.549287] [<ffffffffa00bc59f>] __intel_set_mode+0x7ff/0x1530 [i915] [30553.549302] [<ffffffffa00c2764>] intel_modeset_setup_hw_state+0xab4/0xbb0 [i915] [30553.549312] [<ffffffffa008a2b3>] __i915_drm_thaw+0x143/0x200 [i915] [30553.549314] [<ffffffff810664fc>] ? pc_user_time+0xdc/0x1e0 [30553.549325] [<ffffffffa008ac16>] i915_resume+0x26/0x40 [i915] [30553.549335] [<ffffffffa008ac41>] i915_pm_resume+0x11/0x20 [i915] [30553.549337] [<ffffffff81261df8>] pci_pm_restore+0x78/0xc0 [30553.549339] [<ffffffff81261d80>] ? pci_pm_suspend_noirq+0x190/0x190 [30553.549341] [<ffffffff8130dff6>] dpm_run_callback+0x26/0x60 [30553.549343] [<ffffffff8130e654>] device_resume+0x94/0x190 [30553.549344] [<ffffffff8130e988>] async_resume+0x18/0x40 [30553.549346] [<ffffffff81064662>] async_run_entry_fn+0x32/0x130 [30553.549348] [<ffffffff81058dbd>] process_one_work+0x13d/0x390 [30553.549349] [<ffffffff81059a39>] worker_thread+0x119/0x3a0 [30553.549351] [<ffffffff81059920>] ? manage_workers.isra.30+0x2a0/0x2a0 [30553.549353] [<ffffffff8105f424>] kthread+0xc4/0xe0 [30553.549354] [<ffffffff8105f360>] ? kthread_create_on_node+0x170/0x170 [30553.549356] [<ffffffff814a973c>] ret_from_fork+0x7c/0xb0 [30553.549358] [<ffffffff8105f360>] ? kthread_create_on_node+0x170/0x170 [30553.549359] ---[ end trace 435588afd0af3168 ]--- Also, I've got the problem, that switching from X (my KDE desktop) to a virtual console, the console at my notebook doesn't show the (initial) full brightness while the additionally attached VGA monitor keeps it from beginning. These both things don't need to be connected but may be introduced with the same git-pull: Two weeks ago I've tried a bisect on the WARNING issue which came to the result: {MK.backlight-WARN-message.bisect.log} I have not tested 3.13.x+ kernels after they were outdated. Jani Nikula advised me to file a BUG on here. Jani said: "Attach full dmesg all the way from boot with drm.debug=0xe module parameter set."