Hi Christopher,

Sometime ago, after I reported this bug, I had already updated my BIOS to 2.98:

~ $ sudo dmidecode -s bios-version && sudo dmidecode -s bios-release-date
K01 v02.98
03/18/2015

Since then I've got less video issues, but I cannot tell if they were fixed by the BIOS update or by some other update like the new kernel I have now (3.19).

Those 1-2 minutes freezes definitely have stopped or at least they are not so frequent. But sometimes my Unity still freezes for a few seconds like the first time when I press the Super key to bring up the Dash Home screen or when I run apt-get install and it starts configuring some package. I don't know if they are related. And also I am still seeing i915 crashes and errors in dmesg:


[   10.132760] WARNING! power/level is deprecated; use power/control instead
[   10.287641] [drm:intel_dp_complete_link_train [i915]] *ERROR* failed to update link training
[   10.300577] [drm:intel_dp_complete_link_train [i915]] *ERROR* failed to update link training
[   10.327787] usbcore: registered new interface driver snd-usb-audio
[   10.449263] ------------[ cut here ]------------
[   10.449288] WARNING: CPU: 1 PID: 207 at /build/linux-lts-vivid-3x86XO/linux-lts-vivid-3.19.0/drivers/gpu/drm/i915/intel_display.c:958 intel_disable_pipe+0x2b6/0x2c0 [i91
[   10.449289] pipe_off wait timed out
[   10.449290] Modules linked in: x86_pkg_temp_thermal intel_powerclamp snd_usb_audio kvm_intel snd_usbmidi_lib snd_hda_codec_hdmi hp_wmi snd_hda_codec_realtek snd_hda_code
[   10.449312] CPU: 1 PID: 207 Comm: plymouthd Not tainted 3.19.0-28-generic #30~14.04.1-Ubuntu
[   10.449313] Hardware name: Hewlett-Packard HP Compaq Pro 6300 MT/339A, BIOS K01 v02.98 03/18/2015
[   10.449314]  ffffffffc075f6c8 ffff8802145c3a98 ffffffff817aed97 0000000000002f5c
[   10.449316]  ffff8802145c3ae8 ffff8802145c3ad8 ffffffff81074d8a 00000000fffee53b
[   10.449317]  ffff8800d99f0000 0000000000071008 00000000fffee539 0000000000000001
[   10.449319] Call Trace:
[   10.449324]  [<ffffffff817aed97>] dump_stack+0x45/0x57
[   10.449326]  [<ffffffff81074d8a>] warn_slowpath_common+0x8a/0xc0
[   10.449328]  [<ffffffff81074e06>] warn_slowpath_fmt+0x46/0x50
[   10.449338]  [<ffffffffc06fe126>] intel_disable_pipe+0x2b6/0x2c0 [i915]
[   10.449348]  [<ffffffffc0704d6d>] ironlake_crtc_disable+0xad/0x7c0 [i915]
[   10.449358]  [<ffffffffc0706439>] __intel_set_mode+0xa49/0xc60 [i915]
[   10.449367]  [<ffffffffc070cbb2>] intel_crtc_set_config+0x9e2/0xf60 [i915]
[   10.449377]  [<ffffffffc056783f>] drm_mode_set_config_internal+0x6f/0x110 [drm]
[   10.449381]  [<ffffffffc068a598>] restore_fbdev_mode+0xc8/0xf0 [drm_kms_helper]
[   10.449385]  [<ffffffffc068c4b9>] drm_fb_helper_restore_fbdev_mode_unlocked+0x29/0x80 [drm_kms_helper]
[   10.449395]  [<ffffffffc071a22e>] intel_fbdev_restore_mode+0x1e/0x50 [i915]
[   10.449406]  [<ffffffffc073e88e>] i915_driver_lastclose+0xe/0x20 [i915]
[   10.449411]  [<ffffffffc055ac4e>] drm_lastclose+0x2e/0x130 [drm]
[   10.449415]  [<ffffffffc055b088>] drm_release+0x338/0x540 [drm]
[   10.449418]  [<ffffffff811edf77>] __fput+0xe7/0x220                                                                                                                      
[   10.449420]  [<ffffffff811ee0fe>] ____fput+0xe/0x10                                                                                                                      
[   10.449422]  [<ffffffff81091dc7>] task_work_run+0xb7/0xf0                                                                                                                
[   10.449424]  [<ffffffff81015007>] do_notify_resume+0x97/0xb0                                                                                                             
[   10.449426]  [<ffffffff817b69ef>] int_signal+0x12/0x17                                                                                                                   
[   10.449427] ---[ end trace db2aa3664cf74152 ]---                                                                                                                         
[   10.508008] ip_tables: (C) 2000-2006 Netfilter Core Team                                                                                                                 
[   10.517342] [drm:ironlake_crtc_disable [i915]] *ERROR* failed to disable transcoder B                                                                                    
[   10.519890] [drm:intel_set_pch_fifo_underrun_reporting [i915]] *ERROR* uncleared pch fifo underrun on pch transcoder A                                                   
[   10.519902] [drm:intel_pch_fifo_underrun_irq_handler [i915]] *ERROR* PCH transcoder A FIFO underrun                                                                      
[   10.519914] [drm:intel_set_pch_fifo_underrun_reporting [i915]] *ERROR* uncleared pch fifo underrun on pch transcoder B                                                   
[   10.519922] [drm:intel_pch_fifo_underrun_irq_handler [i915]] *ERROR* PCH transcoder B FIFO underrun