i915 ...FIFO underren...: bug or?

English Install/Boot/Login
1

I just installed openSUSE LEAP 42.1 on an HP Elitebook 8470P: i5-3360M CPU (dual-core, Ivy Bridge, 2.8GHz, intel HD4000 graphics) and noticed some error messages at the top of the console screen relating to errors in i915.

So I checked dmesg:

ron@mashie:~> dmesg |grep i915
    4.110730] [drm] Initialized i915 1.6.0 20150327 for 0000:00:02.0 on minor 0
    4.374949] [drm:intel_set_pch_fifo_underrun_reporting [i915]] *ERROR* uncleared pch fifo underrun on pch transcoder A
    4.374974] [drm:cpt_irq_handler [i915]] *ERROR* PCH transcoder A FIFO underrun
    4.798058] i915 0000:00:02.0: fb0: inteldrmfb frame buffer device
    4.798060] i915 0000:00:02.0: registered panic notifier

After a little work with lspci, I fond the graphics controller:

mashie:/home/ron # lspci -vvs 0:2.0
00:02.0 VGA compatible controller: Intel Corporation 3rd Gen Core processor Graphics Controller (rev 09) (prog-if 00 [VGA controller])
        Subsystem: Hewlett-Packard Company Device 179b
        Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx+
        Status: Cap+ 66MHz- UDF- FastB2B+ ParErr- DEVSEL=fast >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx-
        Latency: 0
        Interrupt: pin A routed to IRQ 32
        Region 0: Memory at d4000000 (64-bit, non-prefetchable) [size=4]
        Region 2: Memory at c0000000 (64-bit, prefetchable) [size=256]
        Region 4: I/O ports at 4000 [size=64]
        Expansion ROM at <unassigned> [disabled]
        Capabilities: [90] MSI: Enable+ Count=1/1 Maskable- 64bit-
                Address: fee00018  Data: 0000
        Capabilities: [d0] Power Management version 2
                Flags: PMEClk- DSI+ D1- D2- AuxCurrent=0mA PME(D0-,D1-,D2-,D3hot-,D3cold-)
                Status: D0 NoSoftRst- PME-Enable- DSel=0 DScale=0 PME-
        Capabilities: [a4] PCI Advanced Features
                AFCap: TP+ FLR+
                AFCtrl: FLR-
                AFStatus: TP-
        Kernel driver in use: i915
        Kernel modules: i915

I then checked lsmod to see which modules related to i915 were loaded:

mashie:/home/ron # lsmod | grep i915
i915                 1196032  6 
i2c_algo_bit           16384  1 i915
drm_kms_helper        139264  1 i915
drm                   385024  8 i915,drm_kms_helper
video                  32768  1 i915
button                 16384  1 i915

So far, everything seems to be working OK (even plasma5), but I want to load KVM and run some VMs. Experience has taught me that the dom0 HW needs to be clean to avoid problems in the VMs, so I’d like to get these errors corrected.

It seems to me that these errors indicate:

  1. A SW bug
  2. Defective HW
    or
    3)Improper configuration

Searching the forum, I see a lot of other people with the same error, so #2 seems unlikely. I also noticed that thses error messages are not restricted to LEAP 42.1, as people running 13.2 have also reported it.

I’m inclined to think it’s a bug, but what other info is needed before I file (or add to) a bug report.

Thank You,
ron[/size][/size][/size]

2

Skimming Google hits,

I’m leaning heavily this is an Intel microcode problem, specific to your hardware (3rd gen i5) running various Linux kernels starting with kernel 3.17x, sometimes reported to be solved with 4.x kernels.

No one seems to know for sure what the actual problem is so it hasn’t been fixed although widely reported across many distros.

Too bad, I’m guessing (again) you may be seeing this problem intermittently on this hardware, probably your best hope is to just bear with it and hope that some kernel upgrade will fix it (without assurance it will remain fixed).

It’s too bothersome, my recommendation is to upgrade/swap your machine. I’d expect some good deal will come around which wouldn’t involve some major expense.

TSU

3

Thanks tsu2. I hadn’t considered faulty microcode when I mentioned defective HW, but your analysis make sense (to me).

So far, the error is consistent and repeatable, it occurs on every boot, but it’s a new (to me) machine which I bought to replace an old MSI laptop that finally had the battery go bad.

So I guess I’ll just have to live with it.

I won’t bother filing a bug report, since it’s widely known and poorly understood, my report would only add to the noise.

Thanks again,
ron