* Dump of registers during endpoint link down @ 2020-07-09 7:14 Manish Raturi 2020-07-09 19:24 ` Bjorn Helgaas 0 siblings, 1 reply; 3+ messages in thread From: Manish Raturi @ 2020-07-09 7:14 UTC (permalink / raw) To: linux-pci Hi Team, I have a generic query , if an hotplug pcie endpoint connected to the CPU root port shows link down, then from the debugging perspective w.r.t PCIE what all register can be dump during the failure condition, what I can think of is these registers from the root port side 1) Link status /control/capability 2) Slot status /control/capability 3) Lane error status registers. Anything else we can dump which gives us more insight into the issue. Also is there anything by which we can check from PCIE clock perspective. Thanks & Regards Manish Raturi ^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: Dump of registers during endpoint link down 2020-07-09 7:14 Dump of registers during endpoint link down Manish Raturi @ 2020-07-09 19:24 ` Bjorn Helgaas 0 siblings, 0 replies; 3+ messages in thread From: Bjorn Helgaas @ 2020-07-09 19:24 UTC (permalink / raw) To: Manish Raturi; +Cc: linux-pci On Thu, Jul 09, 2020 at 12:44:24PM +0530, Manish Raturi wrote: > Hi Team, > > I have a generic query , if an hotplug pcie endpoint connected to the > CPU root port shows link down, then from the debugging perspective > w.r.t PCIE what all register can be dump during the failure condition, > what I can think of is these registers from the root port side > > 1) Link status /control/capability > 2) Slot status /control/capability > 3) Lane error status registers. > > Anything else we can dump which gives us more insight into the issue. > Also is there anything by which we can check from PCIE clock > perspective. If you have this: Root Port ----- Endpoint and the Link is down, you won't be able to read any registers from the Endpoint. You can dump all the Root Port registers, of course, e.g., with "lspci -vvvxxxx". ^ permalink raw reply [flat|nested] 3+ messages in thread
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* Re: Dump of registers during endpoint link down [not found] <CAHn-FMxBZdHPYQkorePnyK+aY_3S29xVnkjj2u3pWDHjTyyGmA@mail.gmail.com> @ 2020-07-13 23:44 ` Bjorn Helgaas 0 siblings, 0 replies; 3+ messages in thread From: Bjorn Helgaas @ 2020-07-13 23:44 UTC (permalink / raw) To: Manish Raturi; +Cc: linux-pci Reply-all and don't top-post. See https://people.kernel.org/tglx/notes-about-netiquette On Mon, Jul 13, 2020 at 03:31:02PM +0530, Manish Raturi wrote: > Thanks, Bjorn, I am doing that (lspci -vvvxxxx) to dump all the > register, but in case of Link down, are there any specific registers > which we should look in, mostly I look below register: > > 1) Link status /control/capability > 2) Slot status /control/capability > 3) Lane error status registers. > > Any other register we can specifically look for. I have no idea what the problem is, so can't really help you, sorry. All you've said is that the link to an endpoint is down. I don't know whether the the slot is even powered up. You could try a different card to see whether that works. You could try the same card in a different machine to see if that works. If you think the link *should* be up, you could always debug it from a hardware point of view with a PCIe analyzer. > On Fri, Jul 10, 2020 at 12:54 AM Bjorn Helgaas <helgaas@kernel.org> wrote: > > On Thu, Jul 09, 2020 at 12:44:24PM +0530, Manish Raturi wrote: > > > Hi Team, > > > > > > I have a generic query , if an hotplug pcie endpoint connected to the > > > CPU root port shows link down, then from the debugging perspective > > > w.r.t PCIE what all register can be dump during the failure condition, > > > what I can think of is these registers from the root port side > > > > > > 1) Link status /control/capability > > > 2) Slot status /control/capability > > > 3) Lane error status registers. > > > > > > Anything else we can dump which gives us more insight into the issue. > > > Also is there anything by which we can check from PCIE clock > > > perspective. > > > > If you have this: > > > > Root Port ----- Endpoint > > > > and the Link is down, you won't be able to read any registers from the > > Endpoint. You can dump all the Root Port registers, of course, e.g., > > with "lspci -vvvxxxx". ^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2020-07-13 23:44 UTC | newest] Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2020-07-09 7:14 Dump of registers during endpoint link down Manish Raturi 2020-07-09 19:24 ` Bjorn Helgaas [not found] <CAHn-FMxBZdHPYQkorePnyK+aY_3S29xVnkjj2u3pWDHjTyyGmA@mail.gmail.com> 2020-07-13 23:44 ` Bjorn Helgaas
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