Hello,
I am having difficulties getting the I2C interrupts to work on an
Intel's Broadwell-DE processors and wondering if someone could help
with this issue.
When i enable the interrupts on I2c_i801 module by removing the
"i2c_i801 disable_feature=0x10" in the options.config file under
/etc/modprobe.d, the I2c commands are failing with transaction
timeout, see log below. These I2C commands work okay if interrupts are
disabled. It seems the CPU never sees the interrupt since the
interrupt counters in /proc/interrupts never increment. see below. If
you look at the PCI config space for the SMBUS device, it shows
interrupts pending on PCISTS register (offset 06-07, bit3), see log
below. Not sure why these are not getting to CPU.
Motherboard is based on Intel's Camelback Mountain CRB. Details are
shown below. As you can see, I am running Debian (Jesse) 4.9.8 but I
also tried 4.11 and it had same behavior. In addition, i also tried
Ubuntu 14.04 but Ubuntu's I2c_i801 driver does not support interrupts.
As shown in /proc/interrupts, linux allocates and activates IRQ=0x12
(18 dec) for the i801_smbus module. I tried verifying the IO-APIC
entry for this interrupt. by passing the "apic=debug" to the linux
command line. As you can see below, the apic entry for pin 12 is
getting enabled and it seems correct. One thing i noticed, however, is
that the interrupt flags (IRQF_TRIGGER*) that are passed by
"devm_request_irq" are ignored. Instead, the ioapic driver hard-wires
these flags during the setup of the IO-APIC. Just to experiment, I
tried changing the polarity to high to see what would happen (based on
spec, it seems these are active low). This actually triggered the
i801_isr (handler) to execute but it was always running and Linux
eventually disables it as a spurious or bad interrupt (no pending flag
in pci space while handler constantly runs).
I tried probing the PIRQC_N (INTC#) signal of the CPU with an
oscilloscope. According to spec and D31IP (Device 31 interrupt Pin
register), the SMBUS controller is mapped and drives this signal
during an interrupt. Signal/scope was not triggering even though the
interrupt went pending in the PCI config space register (PCISTS).
Please, let me know if you have any suggestions, solutions, or require
more info to help me solve this problem. Thanks.
####
@debian:~$ sudo i2cdetect -y 0
0 1 2 3 4 5 6 7 8 9 a b c d e f
00: i801_smbus 0000:00:1f.3: Timeout waiting for interrupt!
i801_smbus 0000:00:1f.3: Transaction timeout
-- i801_smbus 0000:00:1f.3: Timeout waiting for interrupt!
i801_smbus 0000:00:1f.3: Transaction timeout
-- i801_smbus 0000:00:1f.3: Timeout waiting for interrupt!
i801_smbus 0000:00:1f.3: Transaction timeout
-- ^Ci801_smbus 0000:00:1f.3: Timeout waiting for interrupt!
i801_smbus 0000:00:1f.3: Transaction timeout
####
@debian:~$ cat /proc/interrupts
CPU0 CPU1 CPU2 CPU3 CPU4 CPU5
CPU6 CPU7
0: 11 0 0 0 0 0
0 0 IR-IO-APIC 2-edge timer
4: 0 3842 0 0 0 0
0 0 IR-IO-APIC 4-edge serial
9: 0 0 0 0 0 0
0 0 IR-IO-APIC 9-fasteoi acpi
18: 0 0 0 0 0 0
0 0 IR-IO-APIC 18-fasteoi i801_smbus
24: 0 0 0 0 5981 0
0 0 IR-PCI-MSI 512000-edge
###### PCI config space
######
@debian:~$ sudo lspci -s 0000:00:1f.3 -vv -xxx -k
00:1f.3 SMBus: Intel Corporation 8 Series/C220 Series Chipset Family
SMBus Controller (rev 05)
Subsystem: Intel Corporation Device 7270
Control: I/O+ Mem+ BusMaster- SpecCycle- MemWINV- VGASnoop-
ParErr- Stepping- SERR- FastB2B- DisINTx-
Status: Cap- 66MHz- UDF- FastB2B+ ParErr- DEVSEL=medium >TAbort-
<TAbort- <MAbort- >SERR- <PERR- INTx+
Interrupt: pin C routed to IRQ 18
Region 0: Memory at fe41a000 (64-bit, non-prefetchable) [size=256]
Region 4: I/O ports at 2020 [size=32]
Kernel driver in use: i801_smbus
00: 86 80 22 8c 03 00 88 02 05 00 05 0c 00 00 00 00
10: 04 a0 41 fe 00 00 00 00 00 00 00 00 00 00 00 00
20: 21 20 00 00 00 00 00 00 00 00 00 00 86 80 70 72
30: 00 00 00 00 00 00 00 00 00 00 00 00 07 03 00 00
40: 01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
50: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
60: 03 04 04 00 00 00 08 08 00 00 00 00 00 00 00 00
70: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
80: 04 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
90: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
a0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
b0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
c0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
d0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
e0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
f0: 00 00 00 00 00 00 00 00 b1 0f 06 08 00 00 00 00
###### Details
######
@debian:~$ inxi -F
System: Host: debian Kernel: 4.9.8-platina-mk1-amd64 x86_64 (64 bit)
Console: tty 0 Distro: Debian GNU/Linux 8
Machine: Mobo: Intel model: Camelback Mountain Platina DC v: 1.0
Bios: coreboot v: 6a724f1-dirty date: 03/14/2017
CPU: Quad core Intel Xeon D-1527 (-HT-MCP-) cache: 6144 KB
Clock Speeds: 1: 800 MHz 2: 800 MHz 3: 799 MHz 4: 800 MHz
5: 800 MHz 6: 799 MHz 7: 799 MHz 8: 799 MHz
Graphics: Card: Failed to Detect Video Card!
Display Server: N/A driver: N/A
tty size: 80x24 Advanced Data: N/A out of X
Network: Card-1: Broadcom Device b960
IF: N/A state: N/A speed: N/A duplex: N/A mac: N/A
Card-2: Broadcom Device b960
IF: N/A state: N/A speed: N/A duplex: N/A mac: N/A
Card-3: Intel Device 15ab
IF: N/A state: N/A speed: N/A duplex: N/A mac: N/A
Card-4: Intel Device 15ab
IF: N/A state: N/A speed: N/A duplex: N/A mac: N/A
Card-5: Intel I210 Gigabit Network Connection driver: igb
IF: eth0 state: up speed: 1000 Mbps duplex: full
mac: 02:46:8a:00:0b:86
Drives: HDD Total Size: 128.0GB (18.3% used)
ID-1: /dev/sda model: SanDisk_SD8SMAT1 size: 128.0GB
Partition: ID-1: / size: 102G used: 6.8G (7%) fs: ext4 dev: /dev/sda2
ID-2: swap-1 size: 17.06GB used: 0.00GB (0%) fs: swap dev: /dev/sda3
RAID: No RAID devices: /proc/mdstat, md_mod kernel module present
Sensors: None detected - is lm-sensors installed and configured?
Info: Processes: 110 Uptime: 18:05 Memory: 74.6/16014.7MB
Init: systemd runlevel: 5 Client: Shell (bash) inxi: 2.1.28
### dmesg
###
[ 2.547383] request_threaded_irq: irq:12 flags:8
[ 2.551093] Irq Data=(name:(null), mask:0x00000000, irq:0x00000012,
hwirq:0x00000012)
[ 2.551096] ...Activate entry=(Dlvry mode:0x0, Dest mode:0,
Dest:0x00, Vector:0x12, Trigger:1, Polarity:1, Irr:0, Mask:1)
[ 2.551112] request_threaded_irq: irq:12 flags:8
[ 2.554810] i801_smbus 0000:00:1f.3: SMBus using PCI interrupt
[ 2.560181] intel_pstate: Intel P-state driver initializing
[ 2.565603] ip_tables: (C) 2000-2006 Netfilter Core Team
[ 2.570341] NET: Registered protocol family 10
[ 2.574423] NET: Registered protocol family 17
[ 2.578579]
printing PIC contents
[ 2.578584] ... PIC IMR: ffff
[ 2.578588] ... PIC IRR: 04e1
[ 2.578596] ... PIC ISR: 0000
[ 2.578600] ... PIC ELCR: 04e0
[ 2.578603] printing local APIC contents on CPU#0/0:
[ 2.578604] ... APIC ID: 00000000 (0)
[ 2.581719] ... APIC VERSION: 01060015
[ 2.584438] ... APIC TASKPRI: 00000000 (00)
[ 2.584439] ... APIC PROCPRI: 00000000
[ 2.584440] ... APIC LDR: 01000000
[ 2.584442] ... APIC DFR: ffffffff
[ 2.584443] ... APIC SPIV: 000001ff
[ 2.584444] ... APIC ISR field:
[ 2.584447] 0000000000000000000000000000000000000000000000000000000000000000
[ 2.590892] ... APIC TMR field:
[ 2.590894] 0000000000000000000000000000000000000000000000000000000000000000
[ 2.597331] ... APIC IRR field:
[ 2.597333] 0000000000000000000000000000000000000000000000000000000000008000
[ 2.603782] ... APIC ESR: 00000000
[ 2.603783] ... APIC ICR: 000008fd
[ 2.603784] ... APIC ICR2: 20000000
[ 2.603786] ... APIC LVTT: 000400ef
[ 2.603787] ... APIC LVTPC: 00000400
[ 2.603788] ... APIC LVT0: 00010700
[ 2.603789] ... APIC LVT1: 00000400
[ 2.603790] ... APIC LVTERR: 000000fe
[ 2.603792] ... APIC TMICT: 00000000
[ 2.603793] ... APIC TMCCT: 00000000
[ 2.603794] ... APIC TDCR: 00000000
[ 2.603808] number of MP IRQ sources: 15.
[ 2.603809] number of IO-APIC #8 registers: 24.
[ 2.603811] number of IO-APIC #9 registers: 24.
[ 2.603812] testing the IO APIC.......................
[ 2.605676] ata3: SATA link down (SStatus 0 SControl 300)
[ 2.605892] ata6: SATA link down (SStatus 0 SControl 300)
[ 2.608643] ata2: SATA link down (SStatus 0 SControl 300)
[ 2.608679] ata5: SATA link down (SStatus 0 SControl 300)
[ 2.609890] ata4: SATA link down (SStatus 0 SControl 300)
[ 2.609914] ata1: SATA link up 6.0 Gbps (SStatus 133 SControl 300)
[ 2.636442] IO APIC #8......
[ 2.636444] .... register #00: 08000000
[ 2.636445] ....... : physical APIC id: 08
[ 2.636447] ....... : Delivery Type: 0
[ 2.636448] ....... : LTS : 0
[ 2.636449] .... register #01: 00170020
[ 2.636451] ....... : max redirection entries: 17
[ 2.636452] ....... : PRQ implemented: 0
[ 2.636453] ....... : IO APIC version: 20
[ 2.636454] .... IRQ redirection table:
[ 2.636455] IOAPIC 0:
[ 2.636463] pin00, disabled, edge , high, V(00), IRR(0), S(0),
physical, D(00), M(0)
[ 2.636470] pin01, disabled, edge , high, V(00), IRR(0), S(0),
physical, D(00), M(0)
[ 2.636476] pin02, enabled , edge , high, V(02), IRR(0), S(0),
remapped, I(8001), Z(0)
[ 2.636482] pin03, disabled, edge , high, V(00), IRR(0), S(0),
physical, D(00), M(0)
[ 2.636487] pin04, disabled, edge , high, V(00), IRR(0), S(0),
physical, D(00), M(0)
[ 2.636493] pin05, disabled, edge , high, V(00), IRR(0), S(0),
physical, D(00), M(0)
[ 2.636498] pin06, disabled, edge , high, V(00), IRR(0), S(0),
physical, D(00), M(0)
[ 2.636504] pin07, disabled, edge , high, V(00), IRR(0), S(0),
physical, D(00), M(0)
[ 2.636509] pin08, disabled, edge , high, V(00), IRR(0), S(0),
physical, D(00), M(0)
[ 2.636515] pin09, enabled , level, high, V(09), IRR(0), S(0),
remapped, I(40008), Z(0)
[ 2.636520] pin0a, disabled, edge , high, V(00), IRR(0), S(0),
physical, D(00), M(0)
[ 2.636526] pin0b, disabled, edge , high, V(00), IRR(0), S(0),
physical, D(00), M(0)
[ 2.636532] pin0c, disabled, edge , high, V(00), IRR(0), S(0),
physical, D(00), M(0)
[ 2.636538] pin0d, disabled, edge , high, V(49), IRR(0), S(0),
remapped, I(3210642), Z(2)
[ 2.636543] pin0e, disabled, edge , high, V(00), IRR(0), S(0),
physical, D(00), M(0)
[ 2.636549] pin0f, disabled, edge , high, V(00), IRR(0), S(0),
physical, D(00), M(0)
[ 2.636554] pin10, disabled, edge , high, V(00), IRR(0), S(0),
physical, D(00), M(0)
[ 2.636560] pin11, disabled, edge , high, V(00), IRR(0), S(0),
physical, D(00), M(0)
[ 2.636566] pin12, enabled , level, low , V(12), IRR(0), S(0),
remapped, I(C0018), Z(0)
[ 2.636571] pin13, disabled, edge , high, V(00), IRR(0), S(0),
physical, D(00), M(0)
[ 2.636577] pin14, disabled, edge , high, V(00), IRR(0), S(0),
physical, D(00), M(0)
[ 2.636582] pin15, disabled, edge , high, V(00), IRR(0), S(0),
physical, D(00), M(0)
[ 2.636588] pin16, disabled, edge , high, V(1C), IRR(0), S(0),
logical , D(FC), M(2)
[ 2.636594] pin17, disabled, edge , high, V(00), IRR(0), S(0),
physical, D(00), M(0)
[ 2.636597] IO APIC #9......
[ 2.636599] .... register #00: 09000000
[ 2.636600] ....... : physical APIC id: 09
[ 2.636601] ....... : Delivery Type: 0
[ 2.636602] ....... : LTS : 0
[ 2.636603] .... register #01: 00170020
[ 2.636604] ....... : max redirection entries: 17
[ 2.636605] ....... : PRQ implemented: 0
[ 2.636606] ....... : IO APIC version: 20
[ 2.636608] .... register #02: 00000000
[ 2.636609] ....... : arbitration: 00
[ 2.636610] .... register #03: 00000001
[ 2.636611] ....... : Boot DT : 1
[ 2.636612] .... IRQ redirection table:
[ 2.636613] IOAPIC 1:
[ 2.636617] pin00, disabled, edge , high, V(00), IRR(0), S(0),
physical, D(00), M(0)
[ 2.636621] pin01, disabled, edge , high, V(00), IRR(0), S(0),
physical, D(00), M(0)
[ 2.636626] pin02, disabled, edge , high, V(00), IRR(0), S(0),
physical, D(00), M(0)
[ 2.636630] pin03, disabled, edge , high, V(00), IRR(0), S(0),
physical, D(00), M(0)
[ 2.636634] pin04, disabled, edge , high, V(00), IRR(0), S(0),
physical, D(00), M(0)
[ 2.636638] pin05, disabled, edge , high, V(00), IRR(0), S(0),
physical, D(00), M(0)
[ 2.636642] pin06, disabled, edge , high, V(00), IRR(0), S(0),
physical, D(00), M(0)
[ 2.636646] pin07, disabled, edge , high, V(00), IRR(0), S(0),
physical, D(00), M(0)
[ 2.636650] pin08, disabled, edge , high, V(00), IRR(0), S(0),
physical, D(00), M(0)
[ 2.636654] pin09, disabled, edge , high, V(00), IRR(0), S(0),
physical, D(00), M(0)
[ 2.636658] pin0a, disabled, edge , high, V(00), IRR(0), S(0),
physical, D(00), M(0)
[ 2.636662] pin0b, disabled, edge , high, V(00), IRR(0), S(0),
physical, D(00), M(0)
[ 2.636666] pin0c, disabled, edge , high, V(00), IRR(0), S(0),
physical, D(00), M(0)
[ 2.636670] pin0d, disabled, edge , high, V(00), IRR(0), S(0),
physical, D(00), M(0)
[ 2.636674] pin0e, disabled, edge , high, V(00), IRR(0), S(0),
physical, D(00), M(0)
[ 2.636678] pin0f, disabled, edge , high, V(00), IRR(0), S(0),
physical, D(00), M(0)
[ 2.636682] pin10, disabled, edge , high, V(00), IRR(0), S(0),
physical, D(00), M(0)
[ 2.636687] pin11, disabled, edge , high, V(00), IRR(0), S(0),
physical, D(00), M(0)
[ 2.636691] pin12, disabled, edge , high, V(00), IRR(0), S(0),
physical, D(00), M(0)
[ 2.636695] pin13, disabled, edge , high, V(00), IRR(0), S(0),
physical, D(00), M(0)
[ 2.636699] pin14, disabled, edge , high, V(00), IRR(0), S(0),
physical, D(00), M(0)
[ 2.636703] pin15, disabled, edge , high, V(00), IRR(0), S(0),
physical, D(00), M(0)
[ 2.636707] pin16, disabled, edge , high, V(00), IRR(0), S(0),
physical, D(00), M(0)
[ 2.636711] pin17, disabled, edge , high, V(00), IRR(0), S(0),
physical, D(00), M(0)
[ 2.636712] IRQ to pin mappings:
[ 2.636714] IRQ0 -> 0:2
[ 2.636718] IRQ1 -> 0:1
[ 2.636721] IRQ3 -> 0:3
[ 2.636724] IRQ4 -> 0:4
[ 2.636727] IRQ5 -> 0:5
[ 2.636730] IRQ6 -> 0:6
[ 2.636733] IRQ7 -> 0:7
[ 2.636736] IRQ8 -> 0:8
[ 2.636739] IRQ9 -> 0:9
[ 2.636742] IRQ10 -> 0:10
[ 2.636745] IRQ11 -> 0:11
[ 2.636749] IRQ12 -> 0:12
[ 2.636751] IRQ13 -> 0:13
[ 2.636754] IRQ14 -> 0:14
[ 2.636757] IRQ15 -> 0:15
[ 2.636760] IRQ16 -> 0:16
[ 2.636763] IRQ18 -> 0:18
[ 2.636766] IRQ19 -> 0:19
[ 2.636770] .................................... done.
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