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5791 Discussions

Arria 10 PCIe Write DMA Descriptor Controller Registers

Ursa
Beginner
180 Views

Dear All,

I have a simple question but it is important to me and I didn't find an answer in the doc of ug_a10_pcie_avmm.

I think the WR_TABLE_SIZE register is allowed to change on the fly(not only in the initialization stage) by host driver, I just wanted to know if it can take effect at once after changing at anytime. Am I right?

Who can give me the answer yes or no? Thank you very much.

Best regards,

Ursa

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4 Replies
Deshi_Intel
Moderator
174 Views

HI,


I don't think you can change it on the fly as I found below Note from the user guide doc

  • Because the DMA Descriptor Controller uses FIFOs to store descriptor table entries, you cannot reprogram the DMA Descriptor Controller once it begins the transfers specified in the descriptor table. 


Detail in user guide doc (page 82)


Thanks.


Regards,

dlim


Ursa
Beginner
172 Views

@Deshi_Intel Thanks Deshi,

Maybe my wording "on-the-fly" was not accurate, further ask, thus can I change this register in the gap time between two transfers? I just hope the entries of descriptor table can be dynamically changed in run time. Are there any methods?

Best regards,

Ursa

Deshi_Intel
Moderator
167 Views

HI,


If you are referring to "in between 2 transfer" then maybe it's still possible.


Anyway, I encourage you to test it out in hardware to be sure.


Thanks.


Regards,

dlim


Deshi_Intel
Moderator
122 Views

HI,


It's been some time since I last heard from you. I hope you have find the answer by running test run to verify it


For now, I am setting this case to closure.


Feel free to post new forum thread if you still have enquiry in future.


Thanks.


Regards,

dlim


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