linux-5.1.19: i915 when ext HDMI is connected triggers too many interrupts and high load

Submitted by mmokrejs@fold.natur.cuni.cz

Assigned to Intel GFX Bugs mailing list

Link to original bug (#111180)

Description

Hi,
for many years I am using this Dell Vostro 3550 laptop (A12 BIOS version), with Sandybridge CPU and bundled intel graphics. Since a few days, the CPU fan runs at max speed if I connect (as before) a HDMI cable.

On the kernel commandline I had "i915.i915_enable_rc6=1" but I also tried to append "i915.enable_fbc=1" (without any effect).

[ 2.506643] [drm] Disabling ppGTT for VT-d support
[ 2.506734] [drm] VT-d active for gfx access
[ 2.506809] i915 0000:00:02.0: vgaarb: deactivate vga console
[ 2.507340] Console: switching to colour dummy device 80x25
[ 2.507512] [drm] DMAR active, disabling use of stolen memory
[ 2.510243] [drm] Supports vblank timestamp caching Rev 2 (21.10.2013).
[ 2.510248] [drm] Driver supports precise vblank timestamp query.
[ 2.513861] i915 0000:00:02.0: vgaarb: changed VGA decodes: olddecodes=io+mem,decodes=io+mem:owns=io+mem
[ 2.532685] [drm] Initialized i915 1.6.0 20190207 for 0000:00:02.0 on minor 0


$ xrandr
Screen 0: minimum 8 x 8, current 1920 x 1200, maximum 32767 x 32767
LVDS1 connected primary (normal left inverted right x axis y axis)
1366x768 60.05 + 40.01
1280x720 59.74
1024x768 60.00
1024x576 60.00 59.90 59.82
960x540 60.00 59.63 59.82
800x600 60.32 56.25
864x486 60.00 59.92 59.57
640x480 59.94
720x405 59.51 60.00 58.99
680x384 60.00
640x360 59.84 59.32 60.00
DP1 disconnected (normal left inverted right x axis y axis)
HDMI1 connected 1920x1200+0+0 (normal left inverted right x axis y axis) 620mm x 340mm
2048x1152 60.00
1920x1200 59.95*
1920x1080 60.00 60.00 50.00 59.94
1920x1080i 60.00 50.00 59.94
1600x1200 60.00
1680x1050 59.88
1600x900 60.00
1280x1024 75.02 60.02
1280x800 59.91
1152x864 75.00
1280x720 60.00 50.00 59.94
1024x768 75.03 70.07 60.00
832x624 74.55
800x600 72.19 75.00 60.32 56.25
720x576 50.00
720x576i 50.00
720x480 60.00 59.94
720x480i 60.00 59.94
640x480 75.00 72.81 66.67 60.00 59.94
720x400 70.08
VGA1 disconnected (normal left inverted right x axis y axis)
VIRTUAL1 disconnected (normal left inverted right x axis y axis)
$

$ top

top - 19:14:38 up 52 min, 1 user, load average: 1,80, 1,84, 1,94
Tasks: 179 total, 2 running, 177 sleeping, 0 stopped, 0 zombie
%Cpu(s): 0,7 us, 1,0 sy, 0,0 ni, 96,7 id, 0,2 wa, 1,3 hi, 0,2 si, 0,0 st
MiB Mem : 15979,9 total, 13080,3 free, 1618,2 used, 1281,4 buff/cache
MiB Swap: 26224,1 total, 26224,1 free, 0,0 used. 13707,9 avail Mem

PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
9308 root 20 0 0 0 0 I 1,0 0,0 0:01.34 kworker/u8:1-i915-dp
50 root 20 0 0 0 0 R 0,7 0,0 0:16.96 kworker/1:1+events

There are no processes really requiring CPU processing, the high load is supposedly only due to the many interrupts triggered.


$ vmstat 1
procs -----------memory---------- ---swap-- -----io---- -system-- ------cpu-----
r b swpd free buff cache si so bi bo in cs us sy id wa st
3 0 0 13378072 129548 1200160 0 0 135 41 2011 4429 4 3 89 3 0
0 0 0 13378332 129564 1200200 0 0 0 76 3711 7258 0 2 95 4 0
0 0 0 13378332 129564 1200200 0 0 0 0 3707 7380 0 2 98 1 0
0 0 0 13378332 129564 1200200 0 0 0 0 4362 8916 0 3 97 0 0
0 0 0 13378332 129564 1200200 0 0 0 0 4026 7785 0 1 99 0 0
0 0 0 13378332 129564 1200200 0 0 0 0 3623 6965 0 1 99 0 0
1 1 0 13378332 129572 1200192 0 0 0 76 3576 6627 0 2 96 2 0
1 0 0 13378332 129572 1200200 0 0 0 0 3531 6535 1 3 95 1 0
0 0 0 13378332 129572 1200200 0 0 0 0 3600 6947 1 2 97 0 0

cat /proc/interrupts

       CPU0       CPU1       <br>

0: 6 0 IR-IO-APIC 2-edge timer
1: 17 0 IR-IO-APIC 1-edge i8042
8: 0 1 IR-IO-APIC 8-edge rtc0
9: 0 4 IR-IO-APIC 9-fasteoi acpi
12: 0 0 IR-IO-APIC 12-edge i8042
16: 82 0 IR-IO-APIC 16-fasteoi ehci_hcd:usb1
18: 0 0 IR-IO-APIC 18-fasteoi i801_smbus
23: 0 64 IR-IO-APIC 23-fasteoi ehci_hcd:usb2
24: 0 0 DMAR-MSI 0-edge dmar0
25: 0 0 DMAR-MSI 1-edge dmar1
30: 0 0 IR-PCI-MSI 473088-edge pciehp
31: 0 7695604 IR-PCI-MSI 32768-edge i915
32: 0 0 IR-PCI-MSI 360448-edge mei_me
33: 0 26111 IR-PCI-MSI 512000-edge ahci[0000:00:1f.2]
34: 14883 0 IR-PCI-MSI 2621440-edge p1p1
35: 0 35186 IR-PCI-MSI 5767168-edge xhci_hcd
36: 0 0 IR-PCI-MSI 5767169-edge xhci_hcd
37: 0 0 IR-PCI-MSI 5767170-edge xhci_hcd
38: 0 0 IR-PCI-MSI 5767171-edge xhci_hcd
39: 0 0 IR-PCI-MSI 5767172-edge xhci_hcd
40: 0 0 IR-PCI-MSI 442368-edge snd_hda_intel:card0
41: 0 1 IR-PCI-MSI 4718592-edge iwlwifi
NMI: 0 0 Non-maskable interrupts
LOC: 541295 4096293 Local timer interrupts
SPU: 0 0 Spurious interrupts
PMI: 0 0 Performance monitoring interrupts
IWI: 16 642 IRQ work interrupts
RTR: 0 0 APIC ICR read retries
RES: 643529 256795 Rescheduling interrupts
CAL: 58108 32453 Function call interrupts
TLB: 197656 133555 TLB shootdowns
TRM: 3820 3820 Thermal event interrupts
THR: 0 0 Threshold APIC interrupts
MCE: 0 0 Machine check exceptions
MCP: 11 12 Machine check polls
ERR: 0
MIS: 0
PIN: 0 0 Posted-interrupt notification event
NPI: 0 0 Nested posted-interrupt event
PIW: 0 0 Posted-interrupt wakeup event
#

w

19:17:11 up 55 min, 1 user, load average: 1.48, 1.76, 1.90

lspci -vvv -s 00:02.0

00:02.0 VGA compatible controller: Intel Corporation 2nd Generation Core Processor Family Integrated Graphics Controller (rev 09) (prog-if 00 [VGA controller])
Subsystem: Dell 2nd Generation Core Processor Family Integrated Graphics Controller
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 31
Region 0: Memory at f6800000 (64-bit, non-prefetchable) [size=4M]
Region 2: Memory at e0000000 (64-bit, prefetchable) [size=256M]
Region 4: I/O ports at f000 [size=64]
[virtual] Expansion ROM at 000c0000 [disabled] [size=128K]
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


I tried older kernels but I cannot find one with which the issue would disappear. Maybe it was caused by some xfce4 or drm driver update (instead of kernel update) but I cannot figure out which one would that be. At the moment I have x11-drivers/xf86-video-intel-2.99.917_p20190301 and x11-libs/libdrm-2.4.99 (Gentoo Linux).

The fan goes off (and the interrupt rate drops) if I unplug the HDMI cable from the DisplayPort.

The issue is somewhat moderate if I quit X11 and stay in framebuffer console.

Thank you for any clues