Broadcom PEX 8632 Silicon Errata List User guide
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- User guide
Broadcom PEX 8632 Silicon Errata List
Below you will find brief product information for Broadcom PEX 8632 Silicon Errata List. This document details Errata for the following products and silicon revisions:
- Product: PEX 8632
- Description: 32-Lane, 12-Port PCIe Gen 2 Switch
- Revision: AA, AB, BB
The PEX 8632 is a high-performance PCIe Gen 2 switch that provides 32 lanes of connectivity and supports up to 12 ports. It is ideal for use in a variety of applications, including:
- Enterprise servers
- Storage systems
- Networking equipment
- Industrial automation
The PEX 8632 offers a number of features that make it a versatile and powerful solution for a variety of applications. These features include:
Broadcom PEX 8632 Silicon Errata List
Below you will find brief product information for Broadcom PEX 8632 Silicon Errata List. This document details Errata for the following products and silicon revisions:
- Product: PEX 8632
- Description: 32-Lane, 12-Port PCIe Gen 2 Switch
- Revision: AA, AB, BB
The PEX 8632 is a high-performance PCIe Gen 2 switch that provides 32 lanes of connectivity and supports up to 12 ports. It is ideal for use in a variety of applications, including:
- Enterprise servers
- Storage systems
- Networking equipment
- Industrial automation
The PEX 8632 offers a number of features that make it a versatile and powerful solution for a variety of applications. These features include:
PEX 8632
Silicon Revisions and Errata List
CONFIDENTIAL PROPRIETARY INFORMATION
NDA REQUIRED
Version 1.9
June 2011
Website: www.plxtech.com
Technical Support: www.plxtech.com/support
Copyright © 2011 by PLX Technology, Inc. All Rights Reserved – Version 1.9
June 16, 2011
PEX 8632 Errata v1.9
© 2011 by PLX Technology, Inc. All rights reserved. 2
A. Affected Products and Silicon Revisions
This document details Errata for the following products and silicon revisions:
Product Description Revision Status
PEX 8632 32-Lane, 12-Port PCIe Gen 2 Switch
AA General Sampling
AB Conditional Production
BB Full Production
B. Device Documentation Version
The following documentation is the baseline functional description of the silicon:
Document Version Description Publication Date
PEX 8632 Data Book
1.2 Data Book October 2010
C. Errata Documentation Revision History
Revision Publication Date Description
0.5 February 2008
Initial publication of errata list based on errata found
during simulation and evaluation of early silicon samples
(Erratum 1, 2, 3, 4, & 5)
0.6 March 2008
Added Erratum 6
Added Erratum 7
Added Erratum 8
Added Erratum 9
Added Erratum 10
Edited Errata Summary Table (Erratum 3)
0.7 April 2008
Added Erratum 11
Added Erratum 12
Added Erratum 13
Added Erratum 14
0.8 May 2008
Added Erratum 15
Added Erratum 16
Added Erratum 17
Added Erratum 18
0.9 July 2008
Added Erratum 19
Added Erratum 20
Added Erratum 21
Edited Erratum 18
0.91 October 2008
Added Erratum 22
Added Erratum 23
Added Erratum 24
0.92 November 2008
Added Erratum 25
1.0 February 2009
Added Erratum 26
Added Erratum 27
Added Erratum 28
1.1 March 2009
Added Erratum 29
Added Erratum 30
PEX 8632 Errata v1.9
© 2011 by PLX Technology, Inc. All rights reserved. 3
Revision Publication Date Description
1.2 April 2009
Added Erratum 31
Added Erratum 32
Edited Erratum 26 (Workaround #2)
Edited Erratum 30 (Removed Workaround #3)
1.3 June 2009
Edited Erratum 24 (Added Workarounds, Affects BB
Silicon Revision as well)
1.4 September 2009
Added Erratum 33
Added Erratum 34
Edited Erratum 26 (Modified the Description)
1.5 December 2009
Added Erratum 35
Added Caution 1
1.6 January 2010
Edited Erratum 35 (Corrected register bit reference)
Edited Caution 1 (Updated Workaround and Impact)
1.7 March 2010
Added Caution 2
1.8 July 2010
Added Erratum 36
1.9 June 2011
Added Erratum 37
Added Erratum 38
Added Erratum 39
Edited Erratum 30 (Added 3
rd
workaround)
D. Errata Summary
# Description
Risk
Category
Silicon Revisions Affected?
AA AB BB
1 Incorrect Header Log Register Value in NT Mode Low
Yes
Yes
Yes
2 Undependable Lane Reversal with Partial Lanes Low
Yes
No
No
3
Improper Data Rate & De-emphasis Level
Sequence
Low
Yes
No
No
4 Surprise Down Error Messages Not Generated Low
Yes
No
No
5
Link goes Down after Hot Removal in 12-Port
Mode with Partial Lanes
Medium
Yes
No
No
6 Exiting ASPM Causes Link Down Medium
Yes
No
No
7
Unsuccessful Dynamic Link Width/Speed
Change
Low
Yes
No
No
8
ARI Forwarding Supported & Forwarding Enable
Bits
Medium
Yes
No
No
9 Incorrect NT Port Vendor Specific Capability ID Medium
Yes
No
No
10 Incorrect Modified Compliance Pattern Disparity Medium Yes Yes No
11 Flow Control Protocol Error Severity and Low
Yes
No
No
PEX 8632 Errata v1.9
© 2011 by PLX Technology, Inc. All rights reserved. 4
# Description
Risk
Category
Silicon Revisions Affected?
AA AB BB
Surprise Down Severity in Upstream Port
12 Completion Timeout Error Severity Low
Yes
No
No
13
EEPROM Load Cannot Override Strap Pin to
Enable NT
Low
Yes
No
No
14 Stuck in Recovery Low
Yes
No No
15 Scrambler Disable Training Control Bit Low
Yes
Yes No
16
Extended Synch Bit Non-functional in Gen 2
Mode
Low
Yes
Yes No
17
Idle_to_Rlock Transitioned Flag Broken in
Recovery State in Gen 2 Mode
Low
Yes
Yes No
18 EEPROM Loading of Port Configurations Low
Yes
Yes Yes
19 Bad DLLP/TLP Errors in ASPM L1 or L0s Medium
Yes
Yes No
20
Cannot Support 600ppm Offset in Asynchronous
Systems
Low
Yes
Yes Yes
21 Link Speed Change with L1 ASPM Enabled Medium
Yes
Yes No
22 Primary Bus Number 7 Low
Yes
Yes No
23
Broadcast/PME_TURN_OFF TLPs Received
Can Cause Credit Starvation Under Specific
Configuration
Low Yes
Yes No
24 Rx Pins Do Not Work with AC-JTAG Instructions Low Yes Yes Yes
25
Unexpected DL_DOWN in the Middle of TLP
Can Cause FC Credit Loss
Low Yes Yes
No
26 Incorrect TCB Capture of Training Sets
Low Yes
Yes Yes
27
Receiver Error on Virtual Side of Non-
Transparent Port
Low Yes
Yes Yes
28 Correctable Error Status Bit Set Erroneously
Low Yes
Yes Yes
29
Unreliable Port Disable/Re-enable when using
0x234h[19:16]
Low Yes
Yes Yes
30
Legacy Interrupts Cannot be Generated in NT
Mode if Hot Reset Propagation is Disabled
Low Yes Yes Yes
31
Inconsistent Default Value of Power Indicator
Control Register
Low Yes
Yes Yes
PEX 8632 Errata v1.9
© 2011 by PLX Technology, Inc. All rights reserved. 5
# Description
Risk
Category
Silicon Revisions Affected?
AA AB BB
32
Inconsistent Default Value of Power Controller
Control Register if MRL is not locked
Low Yes
Yes Yes
33 Incorrect ACS P2P Completion Routing
Low Yes
Yes Yes
34 ACS Upstream Forwarding Issue Low Yes Yes Yes
35 Analog Loopback Slave Mode Support
Low Yes
Yes Yes
36
Port Arbitration Table can’t be Loaded using the
EEPROM
Low Yes
Yes Yes
37 AC JTAG Functionality Does Not Work
Low Yes
No No
38
Upstream Port LTSSM Exits From Hot-Reset
State After it Receives TS1 With Hot-Reset TCB
Clear
Low Yes Yes Yes
39
PCIe Links Dropped When JTAG Bypass is
Enabled
Low Yes Yes Yes
E. Caution Summary
# Description
Risk
Category
Devices
Excepted
Silicon Revisions Affected?
AA AB BA BB
1
Receivers Detected on Lanes that
Do Not Exit Electrical Idle Polling
Low None
Yes
Yes Yes
Yes
2
Speed Change Bit (TS1) Asserted
After L1 PM State Exit
Low None No No No Yes
PEX 8632 Errata v1.9
© 2011 by PLX Technology, Inc. All rights reserved. 6
F. Errata List
Note: Throughout this document, unless specified otherwise, “Switch” is used to indicate the
PEX 8632 switch.
1. Incorrect Header Log Register Value in NT Mode
Risk Category: Medium Silicon Revisions Affected: AA, AB, BB
Description
This erratum only affects designs using NT Mode.
When a TLP is received on the NT link-side (which is a 64-bit BAR) and the
translated TLP needs to be a 32-bit TLP, if this TLP hits a port that has its
memory enable (for downstream ports) or master enable (for upstream ports)
inactive, the error logging uses the virtual-side address space (the translated
address), but it is tagged with 64-bit flag. Hence, the header log will be a 64-bit
TLP with upper 32 bits 0 instead of its equivalent 32-bit version.
Solution/Workaround
None.
Impact
NT designs using 64 to 32 bit address translation may see an incorrect header
log register value due to this bug.
Back to Errata Summary Table
2. Undependable Lane Reversal with Partial Lanes
Risk Category: Low Silicon Revisions Affected: AA
Description
This erratum only affects designs using lane reversal with partial lanes (some of
the lanes being reversed are not connected to anything) and there is more than 1
port on that station. It does not affect x16 ports.
For example, if a 2-lane (x2) link is being used on a 4-lane (x4) slot and the lanes
are reversed so that Lane 1 is connected to Lane 0 of another device, the link
may not come up if another port on the same station is already linked up.
The same is true if a 2-lane (x2) or 4-lane (x4) device is connected to an 8-lane
(x8) slot and the lanes are reversed to make Lane 1 or Lane 3 to be connected to
the other device’s Lane 0.
Solution/Workaround
None.
PEX 8632 Errata v1.9
© 2011 by PLX Technology, Inc. All rights reserved. 7
Impact
Lane reversal cannot be used for some port configurations if partial lanes are
being used.
Back to Errata Summary Table
3. Improper Data Rate & De-Emphasis Level Sequence
Risk Category: Low Silicon Revisions Affected: AA
Description
The PCI Express Gen2 specification states that data rate and de-emphasis level
settings should repeat the following sequence every time it enters polling
compliance state:
Data Rate = 2.5 GT/s, De-emphasis Level = -3.5 dB.
Data Rate = 5.0 GT/s, De-emphasis Level = -3.5 dB
Data Rate = 5.0 GT/s, De-emphasis Level = -6.0 dB
In the case of the Switch, the sequence is as follows:
Data Rate = 2.5 GT/s, De-emphasis Level = -3.5 dB.
Data Rate = 5.0 GT/s, De-emphasis Level = -6.0 dB
The “Data Rate = 5.0 GT/s, De emphasis Level = -3.5 dB” setting can be
achieved by writing to the Link Control2 register bit 4 and bit 12 and bits 3:0.
Solution/Workaround
None.
Impact
To achieve a data rate of 5.0GT/s and de-emphasis level of -3.5dB, the Link
Control2 register needs to be written to. One of the specification-defined ways to
achieve this (as described above) cannot be used.
Back to Errata Summary Table
4. Surprise Down Error Messages Not Generated
Risk Category: Low Silicon Revisions Affected: AA
Description
The Uncorrectable Error Status register bit 5, Surprise Down Error Status, will not
be set when a link goes down, and the corresponding error message will not be
generated. Also, the data link layer state changed bit in the slot status register is
not reliable.
Solution/Workaround
None.
PEX 8632 Errata v1.9
© 2011 by PLX Technology, Inc. All rights reserved. 8
Impact
Rather than getting an error message in case of a Surprise Down, the system will
need to rely on completion timeouts or polling the link status register for the link-
width.
Back to Errata Summary Table
5. Link Goes Down After Hot Removal in 12-Port Mode with Partial
Lanes
Risk Category: Medium Silicon Revisions Affected: AA
Description
This erratum only affects designs using the Switch in 12-Port Mode.
In 12-Port Mode, the link will continuously go to recovery and no TLP will be
accepted if the following scenario occurs:
1. Link reaches L0 state initially at a width that is less than the programmed
width.
a. The initial link width must be x1 (2.5GT/s or 5.0GT/s).
b. The programmed link width must be x2 (2.5GT/s or 5.0GT/s).
AND
2. A timeout occurs during Recovery.RcvrLock state due to not receiving any
training sets, causing a transition to Detect state.
AND
3. Receiving 2 training sets during state Recovery.RcvrLock before the 24ms
timeout prevents this problem.
Cause: Hot Removal while link state is L0.Active.
Solution/Workaround
If hot removal is needed when the device is strapped as a x2 and is actually a x1
device, a hot reset needs to be given before the next insertion.
Impact
Designs using the Switch in 12-Port Mode and partial lanes (unused lanes) for x2
ports will not be able to use hot insertion after a hot removal.
Back to Errata Summary Table
6. Exiting ASPM Causes Link Down
Risk Category: Medium Silicon Revisions Affected: AA
Description
Going in and out of Active State Power Management States sometimes results in
link retrain or negotiating down the link width.
PEX 8632 Errata v1.9
© 2011 by PLX Technology, Inc. All rights reserved. 9
Solution/Workaround
None (user needs to turn off ASPM).
Impact
If a system BIOS or software is not able to handle link down or link retrain, the
system will hang. Most systems allow ASPM to be turned off, but some systems
may require it.
Back to Errata Summary Table
7. Unsuccessful Dynamic Link Width/Speed Change
Risk Category: Low Silicon Revisions Affected: AA
Description
Dynamically changing link speed or link width from Gen 1 to Gen 2, or vice-
versa, could result in lower speed/width than expected (observed once or twice in
a million events).
Solution/Workaround
Control link speed/width through software controllable registers for dynamic
changes during run time, confirm speed/width and re-program if not correct
value.
Impact
Systems that do not use hardware initiated dynamic speed/width changes should
not be affected by this. In systems where applicable, it may cause the link to
settle in Gen 1 or link up with the wrong width.
Back to Errata Summary Table
8. ARI Forwarding Supported & Forwarding Enable Bits
Risk Category: Medium Silicon Revisions Affected: AA
Description
ARI Forwarding supported bit in Device Capabilities2 Register for a switch
upstream port should be 1’b0 and ARI Forwarding Enable bit in the Device
Control2 Register for the upstream port of a switch should be hardwired to 1’b0.
In the Switch, however, ARI Forwarding supported bit is 1’b1 for the upstream
port and the ARI forwarding enable bit for the upstream port is Read/Writeable.
Solution/Workaround
User needs to disable the upstream port ARI forwarding supported bit using
EEPROM. This also disables the ARI forwarding enable bit Read/Writeable
privilege for the upstream port.
PEX 8632 Errata v1.9
© 2011 by PLX Technology, Inc. All rights reserved. 10
Impact
If customer system is planning to use ARI, EEPROM or I
2
C cycle will be needed
to write to ARI forwarding supported bit before BIOS scan.
Back to Errata Summary Table
9. Incorrect NT Port Vendor Specific Capability ID
Risk Category: Medium Silicon Revisions Affected: AA
Description
For customers using an NT port, the PLX vendor specific capability starts at
address 0xC8 on the type0 header for the Virtual Side and the Link Side uses an
incorrect capability ID of 0xb. It should use the correct ID for vendor specific
capability which is 0x9 (0xb is Compact PCI Central resource control capability).
Solution/Workaround
Standard software would not understand that this is a vendor specific capability
on the NT port.
Impact
Customer software will need to be written in such a way that it understands that
this is a PLX vendor specific capability.
Back to Errata Summary Table
10. Incorrect Modified Compliance Pattern Disparity
Risk Category: Medium Silicon Revisions Affected: AA, AB
Description
The compliance patterns for Lanes 1 thru 7 in each octal of the Switch is
incorrect.
The delay sequence specified by the PCIe 2.0 spec is D D K28.5- D21.5 K28.5+
D10.2 D D where D symbols are K28.5 characters with appropriate disparity.
Lane 0 exhibits the following pattern: K28.5- K28.5+ K28.5- D21.5 K28.5+ D10.2
K28.5- K28.5+ followed by repeating sequences of K28.5- D21.5 K28.5+ D10.2
Lanes 1 thru 7 exhibit the following K28.5+ K28.5- K28.5+ D21.5 K28.5- D10.2
K28.5+ K28.5- followed by repeating sequences of K28.5+ D21.5 K28.5- D10.2.
Solution/Workaround
None.
Impact
The wrong sequence of K28.5+ D21.5 K28.5- D10.2 acts to degrade the high
frequency content of the Compliance Pattern.
Back to Errata Summary Table
PEX 8632 Errata v1.9
© 2011 by PLX Technology, Inc. All rights reserved. 11
11. Flow Control Protocol Error Severity and Surprise Down
Severity in Upstream Port
Risk Category: Low Silicon Revisions Affected: AA
Description
The Flow Control Protocol Error Severity in all ports and the Surprise Down
Severity in the upstream port is hardwired to 1’b0. However, per the PCIe
Specification, it should be hardwired to 1’b1.
Solution/Workaround
None.
Impact
None.
Back to Errata Summary Table
12. Completion Timeout Error Severity
Risk Category: Low Silicon Revisions Affected: AA
Description
In the Switch, the Completion Timeout Error Severity bit is Read/Writeable.
However, per the PCIe Specification, switches do not generate non posted
transactions so all ports of a switch should hardwire this bit to 1’b0.
Solution/Workaround
None.
Impact
None.
Back to Errata Summary Table
13. EEPROM Load Cannot Override Strap Pin to Enable NT
Risk Category: Low Silicon Revisions Affected: AA
Description
The EEPROM load in the Switch is not able to override the strap pin to enable
NT mode.
Solution/Workaround
None.
Impact
Systems that strap the chip to not enable NT mode, and then use an EEPROM to
override the strapping pin to enable NT (0x1DC bit 18), will not be able to do so.
PEX 8632 Errata v1.9
© 2011 by PLX Technology, Inc. All rights reserved. 12
Back to Errata Summary Table
14. Stuck in Recovery
Risk Category: Low Silicon Revisions Affected: AA
Description
There is a state transition in the Recovery state where the Switch does not start
the timers that should cause a timeout if Recovery is not successful. This
transition is from Recovery Idle to Recovery.RcvrLock. This erratum is applicable
in Gen 1 mode as well as Gen 2 mode.
Solution/Workaround
None.
Impact
In a very noisy system, the Switch could get stuck in Recovery when it should
timeout and go to Detect.
Back to Errata Summary Table
15. Scrambler Disable Training Control Bit
Risk Category: Low Silicon Revisions Affected: AA, AB
Description
The Scrambler Disable Training Control bit needs to be latched in the
Configuration Complete state and should not be latched in the Recovery state.
However, the Switch latches the Scrambling Disable Training Control bit in the
Recovery state.
Solution/Workaround
Program the corresponding station Port0 Offset 230h Bit[1] to disable scrambling
for Port0, Bit[5] to disable scrambling for Port1, Bit[9] to disable scrambling for
Port2, and Bit[13] to disable scrambling for Port3.
Impact
Customer will not be able to disable scrambling in the Configuration state. If the
customer tries to enable scramble again, the link will not come up.
Back to Errata Summary Table
16. Extended Synch Bit Non-functional in Gen 2 Mode
Risk Category: Low Silicon Revisions Affected: AA, AB
Description
The Extended Synch bit functionality is non-functional in Gen 2 mode. If the
Extended Synch bit is set in Recovery.RcvrLock state, the transmitter is
PEX 8632 Errata v1.9
© 2011 by PLX Technology, Inc. All rights reserved. 13
supposed to send a minimum of 1024 consecutive TS1 ordered sets before
transitioning to Recovery.RcvrCfg state. However, the Switch keeps on sending
TS1 ordered sets and does not move to Recovery.RcvrCfg state. After a 24ms
timeout, the Switch will attempt to reset the link speed back to Gen 1.
Solution/Workaround
None.
Impact
Customer cannot use the Extended Synch bit in the Switch.
Back to Errata Summary Table
17. Idle_to_Rlock Transitioned Flag Broken in Recovery State in
Gen 2 Mode
Risk Category: Low Silicon Revisions Affected: AA, AB
Description
The idle_to_rlock_transitioned flag does not assert when the Recovery state
machine transitions from Recovery.Idle state to Recovery.RcvrLock state while in
Gen 2 mode. This causes the Recovery state machine to continuously cycle
between Recovery.RcvrLock->Recovery.RcvrCfg->Recovery.Idle states as long
as it is receiving TS2 training sets with valid link and lane numbers. This in turn
leads to a longer than necessary timeout and a delayed return to Detect state.
Solution/Workaround
None.
Impact
It will take a bad link a little longer to go down due to a longer timeout.
Back to Errata Summary Table
18. EEPROM Loading of Port Configurations
Risk Category: Low Silicon Revisions Affected: AA, AB, BB
Description
The EEPROM load of Station 1 and Station 2 port configurations (0x574h) does
not update unless the Station 0 port configuration is also changed during the
EERPOM load.
Solution/Workaround
The EEPROM load to change port configurations needs 1 extra write from the
EEPROM. The first write changes the Station 0 port configuration to a non-strap
value. The second write changes port configurations for all stations to the desired
value.
PEX 8632 Errata v1.9
© 2011 by PLX Technology, Inc. All rights reserved. 14
Impact
The customer may need to execute 1 extra write through the EEPROM if only the
Station 1 and/or Station 2 port configuration(s) need to be changed.
Back to Errata Summary Table
19. Bad DLLP/TLP Errors in ASPM L1 or L0s
Risk Category: Medium Silicon Revisions Affected: AA, AB
Description
If ASPM L1 or L0s is enabled on the Switch, Bad DLLP/TLP errors are logged in
the Switch and spurious NAKs are sent out.
Solution/Workaround
None (user needs to turn off ASPM).
Impact
ASPM L1 and L0s cannot be used.
Back to Errata Summary Table
20. Cannot Support 600ppm Offset in Asynchronous Systems
Risk Category: Low Silicon Revisions Affected: AA, AB, BB
Description
The Switch supports up to a 500ppm offset from other devices in an
asynchronous system as opposed to the 600ppm that the PCIe Base
Specification, r2.0 requires.
Solution/Workaround
Reference clocks need to have tighter control.
Impact
Most clock sources compliant to PCI Express CEM specification exhibit less than
100ppm of frequency variation (including temperature and aging variance). There
should be no impact due to this erratum in CEM Express compliant systems.
Back to Errata Summary Table
21. Link Speed Change with L1 ASPM Enabled
Risk Category: Medium Silicon Revisions Affected: AA, AB
Description
If L1 ASPM is enabled and speed change is requested for a particular link of the
Switch, and the retrain link bit is set, the link will come out of low power state but
the speed change will not take place.
PEX 8632 Errata v1.9
© 2011 by PLX Technology, Inc. All rights reserved. 15
Solution/Workaround
If the link speed does not change on the first try, try again.
Impact
If ASPM is enabled, link speed change may not execute properly.
Back to Errata Summary Table
22. Primary Bus Number for Port 7
Risk Category: Low Silicon Revisions Affected: AA, AB
Description
When software reads the primary bus number for Port 7 on the Switch, the
device returns the value from Port 6 primary bus number register. This issue
affects the read contents returned by the Switch for this register only; the
configuration contents captured, such as bus numbers, Base and Limit settings,
etc. occur normally and the routing of the packets through this port is not
affected.
Solution/Workaround
Do not read the primary bus number register on Port 7.
Impact
Customers using Port 6 or Port 7 as the upstream port will read incorrect values
from the Primary Bus register on Port 7. When the upstream port is neither Port 6
nor Port 7, there is no impact.
Back to Errata Summary Table
23. Broadcast/PME_TURN_OFF TLPs Received Can Cause Credit
Starvation Under Specific Configuration
Risk Category: Low Silicon Revisions Affected: AA, AB
Description
When the Switch is configured as follows:
2-Port (e.g. as a x8, x8 repeater or bridge)
Non-Transparent port is enabled
There is a possibility for the upstream port to consume all credits and stall the
system if it receives vendor-defined Broadcast TLPs or PME_TURN_OFF
message TLP.
Solution/Workaround
Change the configuration of the Switch to have more than two ports.
PEX 8632 Errata v1.9
© 2011 by PLX Technology, Inc. All rights reserved. 16
Impact
The Switch is exposed to this condition when it is configured as described above
and it receives a PME_TURN_OFF TLP or when it is part of a system with
chipsets that generate vendor-defined broadcast TLPs. When the Switch is
configured with three or more ports, there is no impact.
Back to Errata Summary Table
24. Rx Pins Do Not Work with AC-JTAG Instructions
Risk Category: Low Silicon Revisions Affected: AA, AB, BB
Description
The level output on the Switch RX pins used by the AC JTAG instructions is not
stable and consequently it is not latched in the Switch by the boundary scan
chain.
Solution/Workaround
There are two workarounds:
1. Bring up the links and check the widths using the PEX_PORT_GOOD# pins.
The link width and speed can also be checked using I
2
C.
2. The external device can put the Switch into loopback mode and then check
the integrity of the link. External devices connected to the Switch can also be
put in loopback mode using the Switch and the link integrity can be checked
using PRBS or other user-programmable test patterns.
Impact
The RX pins of the Switch cannot be used with AC-JTAG instructions. The TX
pins of the Switch are not affected and can be used with AC-JTAG instructions.
Back to Errata Summary Table
25. Unexpected DL_DOWN in the Middle of TLP Can Cause FC
Credit Loss
Risk Category: Low Silicon Revisions Affected: AA, AB
Description
If a TLP starts on a port of the Switch and a device connected to the Switch is
disconnected either by removing its power supply or by physically disconnecting
it, it is possible that one TLP will not be de-allocated and will consume memory
space until the Switch is reset either by a Fundamental Reset or by a Hot Reset
from the upstream port. The same issue can occur if the noise on the link
manifests itself as an “STP” symbol.
A DL_DOWN due to noise where the device connected to the Switch is sending
at least a few training sets before the link goes down will not have this issue. If
DL_DOWN is caused by noise, the device connected to the Switch is supposed
to go into recovery and send training sets for at least 24ms before the link goes
PEX 8632 Errata v1.9
© 2011 by PLX Technology, Inc. All rights reserved. 17
down. If the Switch receives 2 consecutive good training sets, this erratum will
not occur.
Solution/Workaround
Set the “Link Disable” or “Secondary Bus Reset” bit before removing the link.
Impact
Surprise removal of a device connected to the Switch multiple times can lead to
reduced Switch performance.
Back to Errata Summary Table
26. Incorrect TCB Capture of Training Sets
Risk Category: Low Silicon Revisions Affected: AA, AB, BB
Description
In the case where excess noise exists on a link, the combination of a “COM”
symbol followed by noise can result in the incorrect misinterpretation of Ordered
Sets. The misinterpretation of said sequence might cause the LTSSM to remain
in Loopback State until an assertion of a Hot Reset or a Fundamental Reset is
detected. Due to what is required to create this condition, this problem has only
manifested itself in asynchronous clocked systems.
Solution/Workaround
There are 3 possible workarounds for this erratum:
1. Assert a Hot Rest or Fundamental Reset to the device.
2. Set register 0x228h[5] = 1 in order to mask Training Control Bits (TCB) in
the training sets. Note that setting this bit affects all ports in the station and
if the upstream port is part of the affected station, can cause the upstream
port to ignore the Hot Reset TCB – preventing the switch to be reset from
such a training set.
3. Disable and then enable the failing port using register 0x234h to clear the
LTSSM.
Impact
The link might fail to achieve link-up status due to the noise on the link.
Back to Errata Summary Table
27. Receiver Error on Virtual Side of Non-Transparent Port
Risk Category: Low Silicon Revisions Affected: AA, AB, BB
Description
If a Correctable Error (FC4h), Uncorrectable Error (FB8h), Bad DLLP (1ECh), or
Bad TLP (1E8h) is detected on the Link side of the NT Port, the corresponding
status is reflected on both NT Link and NT Virtual registers on both the NT Link
and NT Virtual interfaces whereas it should only be reflected on the NT Link side.
PEX 8632 Errata v1.9
© 2011 by PLX Technology, Inc. All rights reserved. 18
Solution/Workaround
None.
Impact
The NT Virtual side does not have any link associated with it. Hence, the NT
Virtual Error Registers will reflect an incorrect error status. If the NT Virtual side
error registers have error status set for the one of the errors mentioned above (in
the Description), this error status actually reflects that of the NT Link side.
Back to Errata Summary Table
28. Correctable Error Status Bit Set Erroneously
Risk Category: Low Silicon Revisions Affected: AA, AB, BB
Description
When L0s ASPM is enabled, spurious receiver errors could get logged which
could result in ERR_CORR messages being received by the host.
Solution/Workaround
When L0s ASPM is enabled, set the Correctable Error Mask bit 0xFC8h[0]=1 to
prevent the ERR_CORR message from being sent out due to receiver errors.
Note that when this bit is set, other types of errors could still trigger ERR_CORR
messages if they occur.
Impact
Spurious ERR_CORR messages could be received and the switch might set the
Correctable Error Detected Bit (0x72h[0]) when L0s ASPM is enabled. Although
this erratum occurs when ASPM is enabled, it does not affect the functionality of
ASPM.
Back to Errata Summary Table
29. Unreliable Port Disable/Re-enable when using 0x234h[19:16]
Risk Category: Low Silicon Revisions Affected: AA, AB, BB
Description
If a customer uses register 0x234h[19:16] to disable a particular port when the
link is at Gen 2 speed, the link may not come up when the customer re-enables
the port by clearing these bits back to the default value.
Solution/Workaround
1. To bring a link down, set link disable 0x78h[4] and then set 0x78h[5] to retrain
the link.
2. To disable a port, bring the target link speed to Gen 1 by writing to 0x98h[3:0],
waiting for 10 microseconds, and then using port disable to disable the port.
3. If enabling the port after disabling it does not bring the link up, disable it one
more time and enable it again. This will bring the link up.
PEX 8632 Errata v1.9
© 2011 by PLX Technology, Inc. All rights reserved. 19
Impact
At Gen 2 speed, customer cannot reliably use the port disable/re-enable
functionality of register 0x234h[12:16].
Back to Errata Summary Table
30. Legacy Interrupts Cannot be Generated in NT Mode if Hot Reset
Propagation is Disabled
Risk Category: Low Silicon Revisions Affected: AA, AB, BB
Description
In NT mode, if Hot Reset propagation is disabled by setting 0x1DCh[20] and a
Hot Reset occurs on the upstream port, subsequent doorbell interrupts to the
Root Complex cannot be generated using the doorbell registers. Furthermore,
interrupts from the downstream ports will not be forwarded upstream. Systems
without Hot Reset will not see this erratum.
Solution/Workaround
There are three workaround options:
1. Let the Hot Reset reset the whole device. Do not set 0x1DCh[20].
2. Use MSI in the system if Hot Reset propagation needs to be disabled in the
Switch.
3. Use the Training Control Bit (TCB) Capture Disable bit (0x228[5]) to disable the
Hot Reset rather than the 0x1DC[20] bit.
Impact
If legacy interrupts are needed in a system, a Hot Reset propagation cannot be
disabled on the upstream port of the Switch using 0x1DCh[20]. A Hot Reset is
required to reset the whole device or disabled using 0x228[5].
Back to Errata Summary Table
31. Inconsistent Default Value of Power Indicator Control Register
Risk Category: Low Silicon Revisions Affected: AA, AB, BB
Description
The default values of power indicator control bits [9:8] and attention indicator
control bits [7:6] in the Slot Control register (offset 80h) in the hot plug capable
downstream ports of the Switch are invalid. The legal values should be non-zero,
but these two fields show up as 2‘b00.
Solution/Workaround
Have the software ignore the initial value of the power indicator control and
attention indicator control bits.
PEX 8632 Errata v1.9
© 2011 by PLX Technology, Inc. All rights reserved. 20
Impact
Slight modifications to the software may be needed to ignore the initial default
values of the power indicator control and attention indicator control bits. The
functionality associated with these registers is not affected. Power to the hot plug
capable downstream ports can still be turned on and off normally.
Back to Errata Summary Table
32. Inconsistent Default Value of Power Controller Control Register
if MRL is Not Locked
Risk Category: Low Silicon Revisions Affected: AA, AB, BB
Description
For serial hot plug capable ports, if the MRL is not locked, the value (0 – Power
ON) shown in the power controller control bit [10] of the Slot Control register
(offset 80h) is incorrect. The port(s) is/are actually not powered on (HP_PWREN
is low) which is the correct behavior despite the incorrect default register value.
The port(s) can power ON and OFF normally.
Solution/Workaround
For serial hot plug capable ports, if the MRL is not locked, have the software
ignore the value of the power controller control bit.
Impact
If the MRL is not locked, slight modifications to the software may be needed to
ignore the value of the power controller control bit. The functionality associated
with these registers is not affected. Power to the hot plug capable downstream
ports can still be turned on and off normally.
Back to Errata Summary Table
33. Incorrect ACS P2P Completion Routing
Risk Category: Low Silicon Revisions Affected: AA, AB, BB
Description
If the ACS P2P Completion Redirect bit in the ACS Control and Capability
register is set for a downstream port, completions directed to a peer port from a
peer port without the TLP Relaxed Ordering (RO) bit set should be routed to the
upstream port. However, when the following 2 conditions are met, the Switch
incorrectly routes such completions to the peer port instead:
a) The ACS P2P Egress Control bit is active in the ACS Control and
Capability Register.
b) The Egress Control Vector bit in the ACS Control and Capability register
for the associated egress peer is inactive.
Solution/Workaround
There are two possible workarounds:
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Broadcom PEX 8632 Silicon Errata List User guide
- Type
- User guide
Broadcom PEX 8632 Silicon Errata List
Below you will find brief product information for Broadcom PEX 8632 Silicon Errata List. This document details Errata for the following products and silicon revisions:
- Product: PEX 8632
- Description: 32-Lane, 12-Port PCIe Gen 2 Switch
- Revision: AA, AB, BB
The PEX 8632 is a high-performance PCIe Gen 2 switch that provides 32 lanes of connectivity and supports up to 12 ports. It is ideal for use in a variety of applications, including:
- Enterprise servers
- Storage systems
- Networking equipment
- Industrial automation
The PEX 8632 offers a number of features that make it a versatile and powerful solution for a variety of applications. These features include:
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