Bug 825036
| Summary: | UV2 IO: Need to be able to support more cards with I/O BARs | ||||||
|---|---|---|---|---|---|---|---|
| Product: | Red Hat Enterprise Linux 6 | Reporter: | George Beshers <gbeshers> | ||||
| Component: | kernel | Assignee: | George Beshers <gbeshers> | ||||
| Status: | CLOSED DUPLICATE | QA Contact: | Red Hat Kernel QE team <kernel-qe> | ||||
| Severity: | high | Docs Contact: | |||||
| Priority: | high | ||||||
| Version: | 6.4 | CC: | ctatman, jdonohue, loriann, rja, tee | ||||
| Target Milestone: | rc | Keywords: | FutureFeature | ||||
| Target Release: | 6.4 | ||||||
| Hardware: | x86_64 | ||||||
| OS: | Linux | ||||||
| Whiteboard: | |||||||
| Fixed In Version: | Doc Type: | Enhancement | |||||
| Doc Text: | Story Points: | --- | |||||
| Clone Of: | Environment: | ||||||
| Last Closed: | 2012-11-08 18:01:43 UTC | Type: | Bug | ||||
| Regression: | --- | Mount Type: | --- | ||||
| Documentation: | --- | CRM: | |||||
| Verified Versions: | Category: | --- | |||||
| oVirt Team: | --- | RHEL 7.3 requirements from Atomic Host: | |||||
| Cloudforms Team: | --- | Target Upstream Version: | |||||
| Embargoed: | |||||||
| Bug Depends On: | |||||||
| Bug Blocks: | 746047, 790971, 846704 | ||||||
| Attachments: |
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This request was not resolved in time for the current release. Red Hat invites you to ask your support representative to propose this request, if still desired, for consideration in the next release of Red Hat Enterprise Linux. This request was erroneously removed from consideration in Red Hat Enterprise Linux 6.4, which is currently under development. This request will be evaluated for inclusion in Red Hat Enterprise Linux 6.4. This BZ was fixed in the patchset for BZ#859966 because of a dependency. *** This bug has been marked as a duplicate of bug 859966 *** |
Created attachment 586713 [details] Upstream patch adding nobar cmdline argument Description of problem: commit 7bd1c365fd124624191d49dcc1eb9759d6017ec3 Author: Mike Habeck <habeck> Date: Wed May 12 11:14:32 2010 -0700 x86/PCI: Add option to not assign BAR's if not already assigned The Linux kernel assigns BARs that a BIOS did not assign, most likely to handle broken BIOSes that didn't enumerate the devices correctly. On UV the BIOS purposely doesn't assign I/O BARs for certain devices/ drivers we know don't use them (examples, LSI SAS, Qlogic FC, ...). We purposely don't assign these I/O BARs because I/O Space is a very limited resource. There is only 64k of I/O Space, and in a PCIe topology that space gets divided up into 4k chucks (this is due to the fact that a pci-to-pci bridge's I/O decoder is aligned at 4k)... Thus a system can have at most 16 cards with I/O BARs: (64k / 4k = 16) SGI needs to scale to >16 devices with I/O BARs. So by not assigning I/O BARs on devices we know don't use them, we can do that (iff the kernel doesn't go and assign these BARs that the BIOS purposely didn't assign). This patch will not assign a resource to a device BAR if that BAR was not assigned by the BIOS, and the kernel cmdline option 'pci=nobar' was specified. This patch is closely modeled after the 'pci=norom' option that currently exists in the tree. Signed-off-by: Mike Habeck <habeck> Signed-off-by: Mike Travis <travis> Signed-off-by: Jesse Barnes <jbarnes> Version-Release number of selected component (if applicable): How reproducible: Steps to Reproduce: 1. 2. 3. Actual results: Expected results: Additional info: