https://community.intel.com/t5/Software-Tuning-Performance/can-t-access-RAM-from-PCIe-device-in-Xeon/m-p/1162720#M7091 <P>Hello,</P><P>Is there an known issue of access Xeon's RAM from PCIe (DMA access) ? We observe the issue when using linux 4.x on E5 servers ?<BR />We have this issue only with Xeon E5 + Linux, and using other Intel's chip there is no issue.<BR />When we use the same BIOS, Chip, with windows , we manage to access RAM's from PCIe (DMA access).</P><P>I've tried to search and asked the question, but got no response.<BR />Is it a known issue in this chip ? Why is it observed with Linux , but not with Windows ?<BR />Should I upgrade BIOS or is it some BIOS parameter that I should configure ?</P><P>We also tried to get assistance from Intel's and from Linux kernel, but nothing helped understanding this issue.<BR /><A href="https://bugzilla.kernel.org/show_bug.cgi?id=205701" target="_blank">https://bugzilla.kernel.org/show_bug.cgi?id=205701</A></P><P>We are struggling with this issue for a long time now,</P><P>Any suggestion about this issue will help,&nbsp;</P><P>Ran</P> Thu, 26 Dec 2019 05:49:15 GMT rshal2 2019-12-26T05:49:15Z https://community.intel.com/t5/Software-Tuning-Performance/can-t-access-RAM-from-PCIe-device-in-Xeon/m-p/1162720#M7091 <P>Hello,</P><P>Is there an known issue of access Xeon's RAM from PCIe (DMA access) ? We observe the issue when using linux 4.x on E5 servers ?<BR />We have this issue only with Xeon E5 + Linux, and using other Intel's chip there is no issue.<BR />When we use the same BIOS, Chip, with windows , we manage to access RAM's from PCIe (DMA access).</P><P>I've tried to search and asked the question, but got no response.<BR />Is it a known issue in this chip ? Why is it observed with Linux , but not with Windows ?<BR />Should I upgrade BIOS or is it some BIOS parameter that I should configure ?</P><P>We also tried to get assistance from Intel's and from Linux kernel, but nothing helped understanding this issue.<BR /><A href="https://bugzilla.kernel.org/show_bug.cgi?id=205701" target="_blank">https://bugzilla.kernel.org/show_bug.cgi?id=205701</A></P><P>We are struggling with this issue for a long time now,</P><P>Any suggestion about this issue will help,&nbsp;</P><P>Ran</P> Thu, 26 Dec 2019 05:49:15 GMT https://community.intel.com/t5/Software-Tuning-Performance/can-t-access-RAM-from-PCIe-device-in-Xeon/m-p/1162720#M7091 rshal2 2019-12-26T05:49:15Z