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maximum android phones supported to connect to the usb port on skylake platform


Hi everyone,recently i got some issues about the skylake platform usb connection,as we know ,EHCI is reduced on skylake platform,so we got only XHCI controller to handle all the usb connection,and i have checked the XHCI spec datasheet,it seems like the XHCI controller can handle the maximum 255 usb devices but the single usb device can occupy up to 31 endpoints.


hardware platform:dell optiplex 7050


usb controller: XHCI

in our environment,we need to connect the maximum number of the android phone to test,in the old platform ( dell optiplex 9020),we can connect about 30 phones without any problem,but when it turns to 7050,we can only connect to about 20 phones ,i have used the ms usbview software to check my usb controller status and usb connection,now I got the following problems that need you experts to explain

1、when I press the usb controller (extensible host controller) in the usbview,it says number of ports :26 ,so it means i can only connect maximum 26 usb devices ? i have tried to connect the three ten-ports usb hub,the first two hubs is totally recognized as a ten-ports hub without problem,and the third hub is recognized as a 6-ports hub,so it means even if we use the usb hubs we cannot exceed the maximum port limitation?how is the number 26 calculated?

2、i have connected about 20 andriod phones to the PC,and the rest android phones cannot be totally recognized and stucked in the devicefailedenumeration status,how to maximize the usb to android phone connection?I have checked that per android phone occupy 4 endpoints

3、if I installed a usb expandable card in the pcie slot, will the capacity be more that allow me to successfully connect more usb devices or it just increase the physical usb port quantity?

4、if there is not the function to disable XHCI in the bios setup,any ideas to disable the xhci function inside the windows os ?


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3 Replies

Hello, fosulincong:

Thank you for contacting Intel Embedded Community.

In order to be on the same page, could you please give us the part number of the processors and chipsets related to this consultation?

Could you please give us the name of the manufacturer and model of the PCs related to this situation?

We really appreciate your cooperation to solve this situation.

Waiting for your reply.

Best regards,



Hi carlos:

the cpu model is Intel Core i7-6700


PC Model:dell optiplex 7050

Chipset:Intel Q270 Chipset


Hello, fosulincong:

Thanks for your reply.

It is important to let you know that the information related to your third party PC should be provided by its manufacturer.

By the way, the https://ark.intel.com/products/98088/Intel-Q270-Chipset Intel® Q270 Chipset is out of the scope of support of this channel because it is a non-embedded device.

Due to this fact, we suggest you as a reference address your consultation related to the cited PCs at the following channels:

http://www.dell.com/support/home/us/en/19?c=us&l=en&~ck=mn Support | Dell US

http://www.dell.com/support/contents/us/en/19/category/esupport-order-support?c=us&l=en&~ck=mn Order Support | Dell US

https://www.dell.com/community/Dell-Community/ct-p/English?profile.language=en&~ck=mn Dell Community - Dell Community

http://www.dell.com/support/contents/us/en/19/category/contact-information?c=us&l=en&~ck=mn Contact Information | Dell US

We hope that this information may help you.

Best regards,