Meeting Details
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Jammy
- Linus
- Lorenzo (arm)
- Sami (arm)
- Shameerali (Huawei)
- Sudeep (arm)
- Vincent
- Hanjun
- Jean-Phillip
- Viresh
- Zhangfei (Linaro)
- Jonathoan (Huawei)
- Don
- Sheirlock (Huawei)
- Mattero
- Arnd
WangZhou
- Ulf
Agenda
| Excerpt |
|---|
Under discussion for inclusion
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- IORT
- Shameer: node support - a way to describe memory regions, use case card has FW that needs to allocate host memory. using SMMU no longer needed with IORT
- - patches out for kernel, and ACPI, got a mail from Steve (Arm)
- is IORT version final, ACPI folks asking.
- LP: to check if it is final : JC: Arm usually good at versioning. Sami asked for one minor change to IORT spec.
- SKT: AMD can specify flags, unity mapped, the possibility of holes in VM address space
- LP: are you asking to add something, SKT no not at this time LP: it is worth asking
- LP: what happened with kexec, what happens to the memory, things should be brought back, Steve is looking at this.
- LP: What happens if the kernel resets, JC: ACPI has this, you would need to scan the existing settings.
- LP: could be very complicated, in ACPI can force kernel not to reassign: JC is it "should not"
- JP: need to walk it to solve both cases, but nasty.
- LP: X86 has preserved things, it may just work but likely to have a problem, JP: not assured to happen
- two items to look at
- bdf matching ? → not just a Linux thing,
- kexec → on the list
- JC : don't want to see this patch stall whilst working the other issues
- LP: bdf should not be a blocker, but we should address it
- JP : for 1.0 print warning if RM
- SVA
- discussed with Arm before (JP), violation, need suggestions
- LP:
- JP: was designed correctly at the time of the spec
- LP: for follow calls we need to support the call with a couple of slides have seen patches on the list. Don't think patches will fly if the next generation doesn't need it what then
- JP: I don't think we have the right people, need PCI Sig JC: don't think we need to this Sig, it is a tiny code fix. JP: I think we were planning this fix.
- JC: Is it ok to have quirk fix, but maintainer asked to find a proper fix.
- LP: need SMMU support needed first
- JC: PCI maintainer needed to talk long term fix
- LP: What else, not complicated, just controversial
- JP: virtual SVA, Eric Auger looking at this (not on call)
- LP: there is DT story, be good to have it JC: we don't have a DT so that is hard
- JC: no worries if Arm propose patches with DT
- JP:
- DVFS
- **** Slides ****
Powerpoint name Uncore DVFS.pptx - can use MMIO, PSCI or ACPI (mailbox)
- Do we have any direction for the solution
- VG: for the uncore is it about power or frequency, power down or idle. Have you considered SCMI interface? Hanjun Only supports device tree,
- SH: do you have to have the CPU track Uncore freq : HJ: yes : SH: can you have firmware do it ? JC: not that simple because PCI devices can affect it.
- VG: is the bandwidth affected? " JC: yes: VG: we have this form mobile, you say you have BW requirement. JC: can we use SCMI ? SH: We have to make it work from the spec
- SH: does PCI also need fine-grain control, we might need to add to the spec.
- SH: What are the requirements? HJ: Now we just frequency scale,
- JC: in this case PCI is not enough, it is fiddly to determine.
- HC: We need to gather all the info, need to talk in SWG about DVFS
- JC: would like ACPI to be able to describe the system but unlikely to happen.
- JC: standard SW will not happen any time soon
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