Comment 25 for bug 1432405

I experience the same issue on kernel 4.2-rc6. Before that I needed to boot with the i915.preliminary_hw_support=1 i915.enable_ips=0 kerne parameters, otherwise switching VTs was broken. Now switching works but I get the vblank issue and graphical artifacts. If you need more info or think this is a different bug, please state it so I can open another one. Also contact me if you need more info.

[ 1.546774] ------------[ cut here ]------------
[ 1.546794] WARNING: CPU: 0 PID: 6 at drivers/gpu/drm/drm_irq.c:1162 drm_wait_one_vblank+0x16e/0x1c0 [drm]()
[ 1.546795] vblank not available on crtc 0, ret=-22
[ 1.546844] Modules linked in: msr arc4 bnep bluetooth snd_hda_codec_hdmi iTCO_wdt iTCO_vendor_support intel_rapl iwlmvm iosf_mbi mac80211 nls_iso8859_1 intel_powerclamp coretemp kvm_intel nls_cp437 kvm vfat fat crct10dif_pclmul evdev crc32_pclmul input_leds mac_hid crc32c_intel psmouse serio_raw iwlwifi ghash_clmulni_intel aesni_intel aes_x86_64 lrw snd_hda_codec_conexant gf128mul glue_helper ablk_helper snd_hda_codec_generic cryptd i915 snd_hda_intel rtsx_pci_ms thinkpad_acpi snd_hda_codec memstick snd_hda_core nvram wmi led_class tpm_tis drm_kms_helper battery tpm cfg80211 acpi_pad drm ac snd_hwdep video mei_me rfkill intel_gtt snd_pcm i2c_algo_bit i2c_i801 snd_timer button mei snd lpc_ich soundcore i2c_core shpchp processor sch_fq_codel ip_tables x_tables ext4 crc16 mbcache jbd2 sd_mod rtsx_pci_sdmmc
[ 1.546852] mmc_core atkbd libps2 ahci libahci xhci_pci ehci_pci libata xhci_hcd ehci_hcd usbcore scsi_mod rtsx_pci usb_common i8042 serio
[ 1.546854] CPU: 0 PID: 6 Comm: kworker/u16:0 Tainted: G U 4.2.0-rc6-ARCH #1
[ 1.546855] Hardware name: LENOVO 20DL0029GE/20DL0029GE, BIOS JEET65WW (1.14 ) 05/30/2015
[ 1.546860] Workqueue: events_unbound async_run_entry_fn
[ 1.546863] 0000000000000000 0000000089ad6b61 ffff8802252cb6e8 ffffffff81559be2
[ 1.546865] 0000000000000000 ffff8802252cb740 ffff8802252cb728 ffffffff81073786
[ 1.546867] 0000000100000000 ffff880223cab800 ffff880223cab800 0000000000000000
[ 1.546867] Call Trace:
[ 1.546872] [<ffffffff81559be2>] dump_stack+0x4c/0x6e
[ 1.546875] [<ffffffff81073786>] warn_slowpath_common+0x86/0xc0
[ 1.546877] [<ffffffff81073815>] warn_slowpath_fmt+0x55/0x70
[ 1.546883] [<ffffffffa031e3fe>] drm_wait_one_vblank+0x16e/0x1c0 [drm]
[ 1.546916] [<ffffffffa054ed82>] intel_finish_crtc_commit+0x162/0x170 [i915]
[ 1.546920] [<ffffffffa04341a0>] drm_atomic_helper_commit_planes+0x170/0x200 [drm_kms_helper]
[ 1.546946] [<ffffffffa054ffad>] __intel_set_mode+0x8ad/0xb80 [i915]
[ 1.546973] [<ffffffffa0556e79>] intel_crtc_set_config+0x2c9/0x600 [i915]
[ 1.546980] [<ffffffffa03269f6>] drm_mode_set_config_internal+0x66/0x100 [drm]
[ 1.546983] [<ffffffffa0437522>] restore_fbdev_mode+0xc2/0xf0 [drm_kms_helper]
[ 1.546987] [<ffffffffa0439489>] drm_fb_helper_restore_fbdev_mode_unlocked+0x29/0x70 [drm_kms_helper]
[ 1.546989] [<ffffffffa04394f2>] drm_fb_helper_set_par+0x22/0x40 [drm_kms_helper]
[ 1.547016] [<ffffffffa05656fa>] intel_fbdev_set_par+0x1a/0x60 [i915]
[ 1.547019] [<ffffffff8131c9e8>] fbcon_init+0x538/0x5c0
[ 1.547022] [<ffffffff81395f1e>] visual_init+0xce/0x130
[ 1.547024] [<ffffffff81397a4e>] do_bind_con_driver+0x1be/0x3e0
[ 1.547027] [<ffffffff81397fa9>] do_take_over_console+0x149/0x1a0
[ 1.547029] [<ffffffff81558d87>] ? printk+0x55/0x6b
[ 1.547032] [<ffffffff8131cac7>] do_fbcon_takeover+0x57/0xb0
[ 1.547033] [<ffffffff81320c80>] fbcon_event_notify+0x660/0x760
[ 1.547036] [<ffffffff810920fe>] notifier_call_chain+0x4e/0x80
[ 1.547038] [<ffffffff810924bb>] __blocking_notifier_call_chain+0x4b/0x70
[ 1.547040] [<ffffffff810924f6>] blocking_notifier_call_chain+0x16/0x20
[ 1.547041] [<ffffffff81326a7b>] fb_notifier_call_chain+0x1b/0x20
[ 1.547043] [<ffffffff81328c75>] register_framebuffer+0x215/0x350
[ 1.547047] [<ffffffffa043976f>] drm_fb_helper_initial_config+0x25f/0xaf0 [drm_kms_helper]
[ 1.547071] [<ffffffffa05661ab>] intel_fbdev_initial_config+0x1b/0x20 [i915]
[ 1.547073] [<ffffffff81093c3c>] async_run_entry_fn+0x4c/0x160
[ 1.547076] [<ffffffff8108b4bb>] process_one_work+0x14b/0x440
[ 1.547088] [<ffffffff8108b7f8>] worker_thread+0x48/0x4a0
[ 1.547090] [<ffffffff8108b7b0>] ? process_one_work+0x440/0x440
[ 1.547092] [<ffffffff81091458>] kthread+0xd8/0xf0
[ 1.547094] [<ffffffff81091380>] ? kthread_worker_fn+0x170/0x170
[ 1.547097] [<ffffffff8155f55f>] ret_from_fork+0x3f/0x70
[ 1.547099] [<ffffffff81091380>] ? kthread_worker_fn+0x170/0x170
[ 1.547100] ---[ end trace 601e65f5cbcc5269 ]---