The chassis process (chassisd) could not read I2C data from the indicated device. The CHASSISD_I2C_READ_ERROR message means the chassisd could not read I2C data from the indicated device. The I2C bus is a low-speed bus used to read the I2C EEPROMs on the FRUs/midplane in order to determine the product ID, serial number, temperature, and voltage. When the I2C read error occurs, it cannot read the data and therefore cannot collect the particular outputs being queried.
Below are two examples of the show chassis hardware detail output where no data is showing for the FPC, along with the log messages error:
Example 1
show chassis hardware detail output:
Hardware inventory:
Item Version Part number Serial number Description
Chassis xxxxx T640
Midplane REV 03 710-005608 RBxxxx T640 Backplane
FPM GBUS REV 09 710-002901 JXxxxx T640 FPM Board
FPM Display REV 05 710-002897 JTxxxx FPM Display
CIP REV 06 710-002895 JXxxxx T-series CIP
PEM 0 Rev 14 740-002595 SKxxxxx Power Entry Module
PEM 1 Rev 14 740-002595 SKxxxxx Power Entry Module
SCG 0 REV 12 710-003423 JYxxxx T640 Sonet Clock Gen.
SCG 1 REV 12 710-003423 JYxxxx T640 Sonet Clock Gen.
Routing Engine 0 REV 10 740-008883 Pxxxxxxxxxxx RE-4.0
ad0 245 MB STI Flash 7.3.0 STxxxxxxxxxxxxxxx Compact Flash
ad1 38154 MB FUJITSU MHV2040AS NTxxxxxxxxxx Hard Disk
Routing Engine 1 REV 10 740-008883 Pxxxxxxxxxxx RE-4.0
ad0 245 MB STI Flash 7.3.0 STIxxxxxxxxxxxxxx Compact Flash
ad1 38154 MB FUJITSU MHV2040AS NTxxxxxxxxxx Hard Disk
CB 0 REV 05 710-007655 JWxxxx Control Board (CB-T)
CB 1 REV 05 710-007655 JWxxxx Control Board (CB-T)
FPC 0 <<<<<<<<<<<<< No Data Showing
CPU
FPC 1 REV 02 710-013233 JTxxxx E-FPC Type 3
CPU REV 07 710-010169 JTxxxx FPC CPU-Enhanced
PIC 0 REV 09 750-009567 NHxxxx 1x 10GE(LAN),XENPAK
Xcvr 0 REV 02 740-013170 T06Kxxxxx XENPAK-LR
PIC 1 REV 18 750-007141 WBxxxx 10x 1GE(LAN), 1000 BASE
Log Messages Error:
Dec 10 02:04:17 device-p1_RE0 chassisd[4533]: CHASSISD_I2C_READ_ERROR: i2c_read_ideeprom: read error for group 0 at address 0x51, offset 0
Example 2
show chassis hardware detail output:
Hardware inventory:
Item Version Part number Serial number Description
Chassis JNxxxxxxxxxx MX960
Midplane REV 03 710-013698 TRxxxx MX960 Backplane
FPM Board REV 03 710-014974 KAxxxx MX960 Front Panel Display
PDM Rev 03 740-013110 QCSxxxxxxxx Power Distribution Module
PEM 0 Rev 03 740-013682 QCSxxxxxxxx PS 1.7kW; 200-240VAC in
PEM 1 Rev 03 740-013682 QCSxxxxxxxx PS 1.7kW; 200-240VAC in
PEM 2 Rev 03 740-013682 QCSxxxxxxxx PS 1.7kW; 200-240VAC in
PEM 3 Rev 03 740-013682 QCSxxxxxxxx PS 1.7kW; 200-240VAC in
Routing Engine 0 REV 07 740-013063 1xxxxxxxxx RE-S-2000
ad0 999 MB SILICONSYSTEMS INC 1GB xxxxxxxxxxxxxxx Compact Flash
ad2 38154 MB FUJITSU MHV2040BS NWxxxxxxxxxx Hard Disk
Routing Engine 1 REV 07 740-013063 1xxxxxxxxx RE-S-2000
ad0 999 MB SILICONSYSTEMS INC 1GB xxxxxxxxxxxxxxx Compact Flash
ad2 38154 MB FUJITSU MHV2040BS NWxxxxxxxxxx Hard Disk
CB 0 REV 07 710-013385 KAxxxx MX SCB
CB 1 REV 07 710-013385 KAxxxx MX SCB
CB 2 REV 07 710-013385 KAxxxx MX SCB
FPC 7 REV 04 750-018124 KBxxxx DPCE 4x 10GE R
CPU REV 06 710-013713 Kxxxxx DPC PMB
PIC 0 BUILTIN BUILTIN 1x 10GE(LAN/WAN)
Xcvr 0 REV 01 740-014279 7Xxxxxxxxxxx XFP-10G-LR
FPC 8 <<<<<<<<<<<< No Data Showing
CPU
Fan Tray 0 REV 04 740-014971 TPxxxx Fan Tray
Fan Tray 1 REV 04 740-014971 TPxxxx Fan Tray
Log Messages Error:
Jan 29 02:36:18 chassisd[3244]: CHASSISD_I2C_READ_ERROR: i2c_read_ideeprom: read error for group 26 at address 0x51, offset 0 Jan 29 02:36:18 /kernel: PCF8584(WR): target ack failure on byte 0 Jan 29 02:36:18 /kernel: PCF8584(WR): (i2c_s1=0x08, group=0x1a, device=0x54)
The chassis process could not read the I2C data from the indicated device and as a result there will be no data showing in the output of show chassis hardware detail for that device. The I2C chip fails causing the product ID, serial number, temperature, voltage readouts to fail.
Perform these steps to determine the cause and resolve the problem (if any):
1. Monitor the situation. If the problem only happens a few times a month, it is safe to ignore. The I2C bus is not designed to be 100% reliable, so it is normal that sometimes a read is missed.
2. Try reseating the device. If reseating fails, then there is an issue with the I2C bus that should be researched further. Continue with the next step.
3. Try replacing the device. The issue should follow the component which isn’t being read, as often hardware problems are the root cause of this issue.