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Groups > linux.kernel > #1394273
| From | khalasa@piap.pl (Krzysztof Hałasa) |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: [PATCH REPOST] Extend PCIE_BUS_PEER2PEER to set MRSS=128 to fix CNS3xxx BM DMA. |
| Date | 2016-05-04 15:10 +0200 |
| Message-ID | <rv4IW-4q0-5@gated-at.bofh.it> (permalink) |
| References | <rkrIT-6Ag-37@gated-at.bofh.it> <rqp1F-316-27@gated-at.bofh.it> <rupmr-72T-7@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
Bjorn Helgaas <helgaas@kernel.org> writes: > It looks like 498a92d42596 merely fixed a warning, at the expense of > breaking DMA on Cavium. Reverting it would bring the warning back, but > that's better than broken DMA. Perhaps we should change PCIE_BUS_PEER2PEER to also write MRRS anyway. I realize the CNS3xxx patch is some sort of clever workaround, and that PCIE_BUS_PEER2PEER (which normally comes from kernel command line parameter "pcie_bus_peer2peer") was not exactly intended for this. But if one asks for "peer2peer" (which means limiting transfers to 128 bytes), how could it all work if the bus mastering read requests are not equally limited? BTW s/MRSS/MRRS/g -- Krzysztof Halasa Industrial Research Institute for Automation and Measurements PIAP Al. Jerozolimskie 202, 02-486 Warsaw, Poland
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Re: [PATCH REPOST] Extend PCIE_BUS_PEER2PEER to set MRSS=128 to fix CNS3xxx BM DMA. Bjorn Helgaas <helgaas@kernel.org> - 2016-05-02 19:00 +0200
Re: [PATCH REPOST] Extend PCIE_BUS_PEER2PEER to set MRSS=128 to fix CNS3xxx BM DMA. khalasa@piap.pl (Krzysztof Hałasa) - 2016-05-04 15:10 +0200
Re: [PATCH REPOST] Extend PCIE_BUS_PEER2PEER to set MRSS=128 to fix CNS3xxx BM DMA. Bjorn Helgaas <helgaas@kernel.org> - 2016-05-04 21:50 +0200
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