Created attachment 130233 [details] dmesg The following CPU pipe A underrun can be observed during booting Linux-4.10.X on an Intel SNB processor. It is 100% reproducible during every boot and it occurs before any other software runs. [ 1.071498] [drm] Initialized [ 1.071698] [drm] Disabling PPGTT because VT-d is on [ 1.071714] [drm] Memory usable by graphics device = 2048M [ 1.071717] [drm] VT-d active for gfx access [ 1.071721] [drm] Replacing VGA console driver [ 1.071736] [drm] DMAR active, disabling use of stolen memory [ 1.078093] [drm] Supports vblank timestamp caching Rev 2 (21.10.2013). [ 1.078099] [drm] Driver supports precise vblank timestamp query. [ 1.151068] [drm] Initialized i915 1.6.0 20161121 for 0000:00:02.0 on minor 0 [ 1.365751] fbcon: inteldrmfb (fb0) is primary device [ 2.224399] [drm:intel_cpu_fifo_underrun_irq_handler] *ERROR* CPU pipe A FIFO underrun [ 2.227469] [drm:intel_set_pch_fifo_underrun_reporting] *ERROR* uncleared pch fifo underrun on pch transcoder A [ 2.227478] [drm:cpt_irq_handler] *ERROR* PCH transcoder A FIFO underrun [ 2.414759] i915 0000:00:02.0: fb0: inteldrmfb frame buffer device Full dmesg attached.
And does it go away if you disable VT-d?
Booted with "intel_iommu=igfx_off" and the pipe underrun goes away. I'd prefer to keep VT-d enabled though.
Chris, what is your suggestion here?
Reporter, is this still valid with latest drm-tip?
It happens when booting the Linux kernel, so I guess libdrm is not even involved. I tried it with Linux 4.11.3 and drm master b6f450e0. Result is still the same. [ 1.635652] tsc: Refined TSC clocksource calibration: 2691.258 MHz [ 1.635668] clocksource: tsc: mask: 0xffffffffffffffff max_cycles: 0x26cafc29fa8, max_idle_ns: 440795270837 ns [ 1.886585] [drm:intel_cpu_fifo_underrun_irq_handler] *ERROR* CPU pipe A FIFO underrun [ 1.887064] [drm:intel_set_pch_fifo_underrun_reporting] *ERROR* uncleared pch fifo underrun on pch transcoder A [ 1.887070] [drm:cpt_irq_handler] *ERROR* PCH transcoder A FIFO underrun
(In reply to udo from comment #5) > It happens when booting the Linux kernel, so I guess libdrm is not even > involved. I tried it with Linux 4.11.3 and drm master b6f450e0. > > Result is still the same. > > [ 1.635652] tsc: Refined TSC clocksource calibration: 2691.258 MHz > [ 1.635668] clocksource: tsc: mask: 0xffffffffffffffff max_cycles: > 0x26cafc29fa8, max_idle_ns: 440795270837 ns > [ 1.886585] [drm:intel_cpu_fifo_underrun_irq_handler] *ERROR* CPU pipe A > FIFO underrun > [ 1.887064] [drm:intel_set_pch_fifo_underrun_reporting] *ERROR* uncleared > pch fifo underrun on pch transcoder A > [ 1.887070] [drm:cpt_irq_handler] *ERROR* PCH transcoder A FIFO underrun Hello, I'm changing the status to REOPEN since the problem seems to persist. Thank you.
(In reply to udo from comment #5) > It happens when booting the Linux kernel, so I guess libdrm is not even > Hello, Could you please attach new dmesg with parameter drm.debug=0xe on grub, with the latest kernel? Thank you.
Created attachment 132460 [details] dmesg with drm.debug=0xe Attached dmesg with drm.debug=0xe. The problem occurs at time 1.71
Seems same problem had already been reported at bug 95736, please follow this issue in that bug. *** This bug has been marked as a duplicate of bug 95736 ***
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