Bug 195447 - Limit PCI DMA alias search
Summary: Limit PCI DMA alias search
Status: NEW
Alias: None
Product: Drivers
Classification: Unclassified
Component: PCI (show other bugs)
Hardware: All Linux
: P1 normal
Assignee: drivers_pci@kernel-bugs.osdl.org
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2017-04-17 18:21 UTC by Bjorn Helgaas
Modified: 2017-04-17 18:24 UTC (History)
0 users

See Also:
Kernel Version: v4.10
Subsystem:
Regression: No
Bisected commit-id:

Attachments
lspci -tvn output (2.04 KB, text/plain)
2017-04-17 18:22 UTC, Bjorn Helgaas 		Details
lspci -vv output (149.97 KB, text/plain)
2017-04-17 18:24 UTC, Bjorn Helgaas 		Details
Add an attachment (proposed patch, testcase, etc.)

Description Bjorn Helgaas 2017-04-17 18:21:48 UTC 
pci_for_each_dma_alias() normally iterates all the way up to the root of a PCI hierarchy.  But on some systems the IOMMU is attached below the root, and DMA aliases generated above the IOMMU are useless.

Jayachandran C <jnair@caviumnetworks.com> has proposed patches to limit the DMA alias search on ThunderX2.  These are planned for v4.12.

The purpose of this bugzilla is only to archive lspci output showing the unusual topology of ThunderX2.
Comment 1 Bjorn Helgaas 2017-04-17 18:22:38 UTC 
Created attachment 255905 [details]
lspci -tvn output
Comment 2 Bjorn Helgaas 2017-04-17 18:24:09 UTC 
Created attachment 255907 [details]
lspci -vv output
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