[Intel-gfx] Possible 4.5 i915 Skylake regression

Sun Mar 13 22:41:45 UTC 2016

On Wed, Feb 17, 2016 at 8:18 AM, Daniel Vetter <daniel at ffwll.ch> wrote:
> On Tue, Feb 16, 2016 at 09:26:35AM -0800, Andy Lutomirski wrote:
>> On Tue, Feb 16, 2016 at 9:12 AM, Andy Lutomirski <luto at amacapital.net> wrote:
>> > On Tue, Feb 16, 2016 at 8:12 AM, Daniel Vetter <daniel at ffwll.ch> wrote:
>> >> On Mon, Feb 15, 2016 at 06:58:33AM -0800, Andy Lutomirski wrote:
>> >>> On Sun, Feb 14, 2016 at 6:59 PM, Andy Lutomirski <luto at kernel.org> wrote:
>> >>> > Hi-
>> >>> >
>> >>> > On 4.5-rc3 on a Dell XPS 13 9350 (Skylake i915, no nvidia on this
>> >>> > model), shortly after resume, I saw a single black flash on the
>> >>> > screen.  The log said:
>> >>> >
>> >>> > [Feb13 07:05] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR*
>> >>> > CPU pipe A FIFO underrun
>> >>> >
>> >>> > I haven't seen this on 4.4.
>> >>> >
>> >>> > I'd be happy to dig up debugging info, but I don't know what would be
>> >>> > useful.  I have no i915 module options set.
>> >>>
>> >>> It's flashing quite frequently now, although I seem to get the
>> >>> underrun warning only once per resume.
>> >>
>> >> We shut up the warning irq source to avoid hijacking an entire cpu core
>> >> ;-)
>> >>
>> >> There's a fix from Matt right after 4.5-rc4 in Linus' branch. I'm hoping
>> >> that should help.
>> >
>> > Do you mean:
>> >
>> > commit e2e407dc093f530b771ee8bf8fe1be41e3cea8b3
>> > Author: Matt Roper <matthew.d.roper at intel.com>
>> > Date:   Mon Feb 8 11:05:28 2016 -0800
>> >
>> >     drm/i915: Pretend cursor is always on for ILK-style WM calculations (v2)
>> >
>> > If so, it didn't help.  I'm currently doing a full rebuild just in
>> > case I messed something up, though.
>> >
>>
>> Definitely not fixed.  It seems to be okay after a reboot until the
>> first suspend/resume.
>>
>> This happened after resuming.  Five cents says it's the root cause.
>
> That's interesting, but doesn't ring a bell unfortunately. Can you try to
> attempt a bisect?
>

I'm giving up on my attempt to bisect for now.  After a bunch of false
starts to avoid this crap, I'm stuck at
651174a4a0ccaf41e14fadc4bc525d61ae7f7b18, which is based on 4.3-rc3
and doesn't merge cleanly up to 4.4.  It's also annoying because it
reproduces reasonably quickly but not instantaneously, and I can never
reproduce it before a suspend/resume, so my bisection attempts are
full of errors.

--Andy

> Thanks, Daniel
>
>>
>> [  160.361200] WARNING: CPU: 2 PID: 2512 at
>> drivers/gpu/drm/i915/intel_uncore.c:599
>> hsw_unclaimed_reg_debug+0x69/0x90 [i915]()
>> [  160.361209] Unclaimed register detected before writing to register 0x20a8
>> [  160.361213] Modules linked in: rfcomm fuse ccm cmac xt_CHECKSUM
>> ipt_MASQUERADE nf_nat_masquerade_ipv4 tun nf_conntrack_netbios_ns
>> nf_conntrack_broadcast ip6t_rpfilter ip6t_REJECT nf_reject_ipv6
>> xt_conntrack ebtable_filter ebtable_nat ebtable_broute bridge stp llc
>> ebtables ip6table_raw ip6table_mangle ip6table_security ip6table_nat
>> nf_conntrack_ipv6 nf_defrag_ipv6 nf_nat_ipv6 ip6table_filter
>> ip6_tables iptable_raw iptable_mangle iptable_security iptable_nat
>> nf_conntrack_ipv4 nf_defrag_ipv4 nf_nat_ipv4 nf_nat nf_conntrack bnep
>> arc4 iwlmvm mac80211 snd_hda_codec_hdmi snd_hda_codec_realtek
>> hid_multitouch snd_hda_codec_generic iwlwifi snd_hda_intel intel_rapl
>> snd_hda_codec x86_pkg_temp_thermal coretemp kvm_intel snd_hwdep
>> cfg80211 snd_hda_core kvm snd_seq uvcvideo snd_seq_device
>> i2c_designware_platform
>> [  160.361385]  i2c_designware_core btusb snd_pcm videobuf2_vmalloc
>> wmi_mof vfat dell_wmi fat videobuf2_memops btrtl btbcm btintel
>> bluetooth dell_laptop dell_smbios dcdbas videobuf2_v4l2 snd_timer
>> videobuf2_core rtsx_pci_ms snd irqbypass videodev memstick
>> ghash_clmulni_intel joydev mei_me efi_pstore mei i2c_i801 soundcore
>> efivars pcspkr idma64 shpchp virt_dma media rfkill intel_lpss_pci
>> processor_thermal_device intel_soc_dts_iosf wmi acpi_als kfifo_buf
>> int3403_thermal tpm_tis industrialio pinctrl_sunrisepoint tpm
>> intel_hid int3400_thermal pinctrl_intel intel_lpss_acpi sparse_keymap
>> int340x_thermal_zone acpi_thermal_rel intel_lpss nfsd acpi_pad
>> auth_rpcgss nfs_acl lockd binfmt_misc grace sunrpc dm_crypt i915
>> i2c_algo_bit drm_kms_helper syscopyarea sysfillrect sysimgblt
>> fb_sys_fops drm rtsx_pci_sdmmc
>> [  160.361548]  mmc_core crct10dif_pclmul crc32_pclmul crc32c_intel
>> rtsx_pci serio_raw i2c_hid video
>> [  160.361575] CPU: 2 PID: 2512 Comm: gnome-shell Not tainted
>> 4.5.0-rc4-acpi+ #59
>> [  160.361581] Hardware name: Dell Inc. XPS 13 9350/07TYC2, BIOS 1.1.9
>> 12/18/2015
>> [  160.361588]  0000000000000086 00000000604232f7 ffff88024d55ba60
>> ffffffff81449d83
>> [  160.361601]  ffff88024d55baa8 ffffffffa01e15e8 ffff88024d55ba98
>> ffffffff81094252
>> [  160.361612]  ffff88026f4d0000 00000000000020a8 ffff88026f4d0000
>> 00000000fffffefe
>> [  160.361624] Call Trace:
>> [  160.361644]  [<ffffffff81449d83>] dump_stack+0x65/0x92
>> [  160.361660]  [<ffffffff81094252>] warn_slowpath_common+0x82/0xc0
>> [  160.361671]  [<ffffffff810942ec>] warn_slowpath_fmt+0x5c/0x80
>> [  160.361764]  [<ffffffffa0158469>] hsw_unclaimed_reg_debug+0x69/0x90 [i915]
>> [  160.361844]  [<ffffffffa015b71e>] gen9_write32+0x6e/0x390 [i915]
>> [  160.361855]  [<ffffffff810b86a5>] ? preempt_count_add+0x85/0xd0
>> [  160.361939]  [<ffffffffa014d955>] gen8_logical_ring_get_irq+0x95/0xe0 [i915]
>> [  160.362017]  [<ffffffffa013b4db>] __i915_wait_request+0x58b/0x650 [i915]
>> [  160.362028]  [<ffffffff810d7380>] ? wake_atomic_t_function+0x70/0x70
>> [  160.362113]  [<ffffffffa013b70e>]
>> i915_gem_object_wait_rendering__nonblocking+0x16e/0x2c0 [i915]
>> [  160.362200]  [<ffffffffa0141c34>] ? i915_gem_pwrite_ioctl+0xe4/0x9b0 [i915]
>> [  160.362211]  [<ffffffff810b86a5>] ? preempt_count_add+0x85/0xd0
>> [  160.362225]  [<ffffffff81857486>] ? _raw_write_unlock+0x16/0x30
>> [  160.362312]  [<ffffffffa013eed9>] i915_gem_set_domain_ioctl+0x99/0x160 [i915]
>> [  160.362357]  [<ffffffffa00887c2>] drm_ioctl+0x152/0x540 [drm]
>> [  160.362439]  [<ffffffffa013ee40>] ?
>> i915_gem_object_set_to_gtt_domain+0x180/0x180 [i915]
>> [  160.362456]  [<ffffffff813d30bd>] ? selinux_file_ioctl+0x11d/0x200
>> [  160.362469]  [<ffffffff81240521>] do_vfs_ioctl+0xa1/0x5b0
>> [  160.362480]  [<ffffffff81852c5d>] ? __schedule+0x3ad/0xa80
>> [  160.362492]  [<ffffffff81240aa9>] SyS_ioctl+0x79/0x90
>> [  160.362505]  [<ffffffff81857bae>] entry_SYSCALL_64_fastpath+0x12/0x71
>> [  160.362515] ---[ end trace d66ecf0dd3c2adc4 ]---
>> [...]
>> [  249.526574] [drm:intel_cpu_fifo_underrun_irq_handler [i915]]
>> *ERROR* CPU pipe A FIFO underrun
>
> --
> Daniel Vetter
> Software Engineer, Intel Corporation
> http://blog.ffwll.ch

-- 
Andy Lutomirski
AMA Capital Management, LLC