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<p class="MsoNormal"><span lang="EN-US">Hi DPDK,<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">I am a pmd driver developer from Realtek NIC department,
<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">when I was porting r8168pmd already verified on x86 to an ARM64 SoC Unisoc: UIS8650<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">I found that after NIC Rx init (in general, Rx ring and buffers should have been prepared for NIC to DMA read),
<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">the NIC status reg showed RDU (Rx Descriptor Unavailable), which means NIC cannot read the proper desc content,<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">later I sended some packets to NIC hold by testpmd rx_only mode, HW internal Rx packet counter can grow to some value, then stuck, 8168pmd Rx debug print reported it received less packets than that value, and the print
showed up even some minutes later!<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">I doubt the phenomenon is caused by improper HW-based IO coherency support on this ARM SoC,<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">I have read the ARM SoC support list on DPDK website, to name it: NV Bluefield, NXP DPAA, Marvell Octeon TX
</span>…<span lang="EN-US"><o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">Does DPDK (or UIO/VFIO driver or hugetlb driver) need special HW IO cache coherency support on ARM platform, say, ACE and Device side MMU etc?<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">Should the SoC provide specialized UIO/VFIO driver or hugetlb driver and/or specific DPDK lib to support such user mode DMA?<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">Will you please give<span style="color:#1F497D">
</span>suggestions, thanks a lot!<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">BRs<o:p></o:p></span></p>
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