C3558 ,PCIe GEN3x4 device can only be plugged after the BIOS is running

[hui_cq]

C3558 is connected to switch chip use PCIe GEN3x4 HSIO, if release reset of switch chip during the BIOS starting，BIOS will be stopped, screen print "92" . After the bios is running, it is about 30s, then release reset of switch chip, PCIe will work normally, why this happens ?

[CarlosAM_INTEL]

Hello, @hui_cq :

Thank you for contacting Intel Embedded Community.

Based on your previous communication, we want to address the following questions:

Could you please let us know if your questions are related to a third-party device or a design developed by you?

Could you please give us the part number, name of the manufacturer, and where to find the information of the third-party device related to this thread?

Could you please list the sources used to develop your design? By the way, could you please clarify that Intel reviewed your design?

We are waiting for your answer to these questions.

Best regards,

@CarlosAM_INTEL.

[hui_cq]

Thank you for your reply! I think  this problem is not related to third-party device. It is related to the BIOS. If we close the debug information print to serial port in BIOS, the reset release delay time is about 30S, if we open the debug information print to serial port in BIOS, the reset release delay time  is about 60S. The only difference is BIOS. But we don't  know which point will have an influence on this in BIOS.

[CarlosAM_INTEL]

Hello, @hui_cq:

Thanks for your reply.

Based on your previous communication, could you please let us know the name of the developer of the affected BIOS and its version?

By the way, the information requested in your previous communication gives us information that may help us to better understand this situation, could you please look into the previous questions and let us know the information that may answer them?

We are waiting for your answer.

Best regards,

@CarlosAM_INTEL.

[hui_cq]

BIOS information：Version 2.19.1266. Copyright (C) 2021 American Megatrends, Inc.

The part number of switch chip is CTC8180,  provided by CENTEC network，a company from China. Actually,  this is not helpful. 

Intel has already reviewed our design through CCE platform. https://ccechina.intel.cn/

In our design，we use PMU_PLTRST_N signal  which is provided by CPU  to release the reset of switch chip. if no delay or short delay is added, the BIOS can not work normally, stop at "92" which means “pci bus initialization is started” . If it is delayed 30S with debug information print closed or 60S with debug information print opened, the PCIe will wok normally. All these are directed to BIOS but not to switch chip. Could you please give us some advise on how to investigate why the BIOS stops at "92"  ?

[CarlosAM_INTEL]

Hello, @hui_cq:

Thanks for your update.

Based on your last communication, could you please clarify if the C3558 related to your question is part of the CTC8180 implementation?

We are waiting for your answer.

Best regards,

@CarlosAM_INTEL. 

[hui_cq]

Yes,C3558 connects to CTC8180 through HSIO0~3, working mode is PCIe3.0

[CarlosAM_INTEL]

Hello, @hui_cq:

Thanks for your reply.

Your design with the C3558 has been verified by Intel.

Due to this fact, could you please verify with the manufacturer of the third-party device that you want to interface with your design their compatibility? You should address this question as a reference through the Technical Support email address located on the bottom of the following website:

https://www.centecnetworks.com/

Best regards,

@CarlosAM_INTEL.

[hui_cq]

Thanks for your reply!

We have already discussed this issue with engineers from CENTEC.

After BIOS is running, then release the reset of switch chip, PCIe can work normally. So compatibility is OK, both sides can support PCIe3.0. The only difference is configuration in CPU before and after BIOS running . How to find this difference?

[CarlosAM_INTEL]

Hello, @hui_cq:

Thanks for your reply.

We suggest using the latest version of the BIOS and microcode. You should find the cited microcode on the following website:

https://github.com/platomav/CPUMicrocodes/blob/master/Intel/cpu506F1_plat01_ver00000034_2020-10-23_PRD_1E364CDF.bin

You should contact the mentioned BIOS developer to help you with your BIOS version verification or questions.

You should update your Resource and Design Center (RDC) to privilege account to give you more details.

The RDC Account Support form is the channel to process your account update process by filling out the form stated on the following website:

https://www.intel.com/content/www/us/en/forms/support/my-intel-sign-on-support.html

Best regards,

@CarlosAM_INTEL.