How to stop or cancel an “Read/Write AVMM DMA operation” after it begins ?

[JET60200]

Hi Intel experts,

Sometimes I saw  Arria10  " PCIe AVMM DMA operation” would consume much more time than it's expected.  Such as in normal case, the DMA operation will consume around “+35us” to complete its Task in the Descriptor Table, while in rare exceptional case, the DMA will consume around "+3000us" (or above) to complete a similar task in Desc table, which will break down our System Timing.  

So I wonder whether there's any method to "Stop or Cancel" that current "exceptional" AVMM DMA operation, when we found it exceed EXPECTED duration. I check "AVMM User Guide", unfortnately found nothing about it.  

If any one has some suggestion, that's great appreciated.  Thanks a lot

@SengKok_L_Intel , please help if convenient, Thanks

[SengKok_L_Intel]

Hi,

One possible solution is to generate the Secondary Bus Reset from the host. It is available at the Bridge Control register Bit 6.

Regards -SK

[JET60200]

" One possible solution is to generate the Secondary Bus Reset from the host. It is available at the Bridge Control register Bit 6. "

-> Hello @SengKok_L_Intel ,

Sorry for the delay ,  but which document describes the mentioned " Bridge Control Register "  ?  

Pls help to point it out,  so i could check it detailedly.  thanks

[SengKok_L_Intel]

You can search the "secondary bus reset" or "bridge control register" from the PCIe spec. 

[JET60200]

Thanks @SengKok_L_Intel  for quick feedback,

I have no more questions on this ticket,  thanks for kindly support！

[SengKok_L_Intel]

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