Hi Bjorn, > -----Original Message----- > From: linux-pci-owner@xxxxxxxxxxxxxxx [mailto:linux-pci- > owner@xxxxxxxxxxxxxxx] On Behalf Of Rajat Jain > Sent: Tuesday, January 07, 2014 10:21 AM > To: Bjorn Helgaas; Rajat Jain > Cc: Rajat Jain; Kenji Kaneshige; Alex Williamson; Yijing Wang; linux- > pci@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; Yinghai Lu; Guenter > Roeck; Yinghai Lu > Subject: RE: [PATCH v3 4/8] pciehp: Don't disable the link permanently, > during removal > > Hello Bjorn / Yinghai, > > > -----Original Message----- > > From: Bjorn Helgaas [mailto:bhelgaas@xxxxxxxxxx] > > Sent: Monday, January 06, 2014 4:04 PM > > To: Rajat Jain > > Cc: Rajat Jain; Kenji Kaneshige; Alex Williamson; Yijing Wang; linux- > > pci@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; Yinghai Lu; Guenter > > Roeck; Rajat Jain; Yinghai Lu > > Subject: Re: [PATCH v3 4/8] pciehp: Don't disable the link > > permanently, during removal > > > > On Sun, Jan 5, 2014 at 10:53 AM, Rajat Jain <rajatxjain@xxxxxxxxx> > > wrote: > > > Hello Bjorn, > > > > > > Just checking on the fate of this patch set... > > > > > > On Tue, Dec 17, 2013 at 5:02 PM, Bjorn Helgaas <bhelgaas@xxxxxxxxxx> > > wrote: > > >> [+cc yinghai@xxxxxxxxxx (seems to be Yinghai's preferred email] > > >> > > >> On Tue, Dec 17, 2013 at 12:06:05PM -0800, Rajat Jain wrote: > > >>> We need future link up events for hot-add, thus don't disable the > > >>> link permanently during device removal. Also, remove the static > > >>> functions that are now left unused. > > >> > > >> The changelog should mention that this reverts part of 2debd9289997 > > ("PCI: > > >> pciehp: Disable/enable link during slot power off/on"). > > > > > > Sure. Do you want me to submit another patch set (bumping up the > > > version) with this change log, or you'd want to add this change log > > > while merging? > > > > > >> > > >> Yinghai, can you tell us whether this is an issue on your systems? > > > > > > As Yinghai confirms further down this thread, his issue was > > > confirmed by Intel to be a bug in the repeater chip. > > > ---------------------------------- > > > Yinghai writes: > > >> According to HW guys and Intel, that should be bug of repeater. > > >> > > > --------------------------------- > > > I don't know about the details of his scenario, except that when > > > the adapter was disabled the repeater kept on flapping the link up & > > > down (and hence disabling the link solved the problem then). Yinghai > > > couldn't test, but I believe with this patch even if we disable > > > presence detect interrupt, the "adapter present / no present" > > > messages would (rightly) convert to "Link Up / Link Down" messages > > > (since the repeater keeps on flapping the link). > > > > > > Since it is a platform specific bug, I'm not sure what can be done > > > to remove those messages except may be reduce the verbosity? If > > > you'd like I could change all the INFO messages to DBG messages. > > > > Even if it's a defect in a particular piece of hardware, I don't want > > to regress on that hardware, even if the regression is just extra > > messages that we didn't see before. > > > > I think ideally we would add some sort of quirk for that hardware so > > it works just as well as it does today. I think extra messages will > > lead to a bug reports from users. > > Sure, I can do that. I think what the quirk would have to do is that for > that particular platform, don't enable the link-state based hotplug. > (Since link-state hotplug will not work if we disable the link > permanently as we do today on card removal). > > But the question is how to determine that the quirk has to be applied? I > think the objective is to apply the quirk to the platforms that have a > "PCIe repeater". Since this does not depend on a PCI device / vendor ID, > and I think the PCIe repeater is probably not even visible to the pciehp > or the PCI subsystem, how do I determine that the quirk has to be > applied? Any ideas on how do I identify the platforms that may have this problem? Thanks, Rajat > > If (hw_has_pcie_repeater) > Don't use link-state hotplug (and disable link permanently during > card removal) Else > Use link-state hotplug (and don't disable the link permanently) > > > Yinghai: Since I do not have that hardware, I will need some help in > testing the patch with the quirk. I was wondering if you'd still have > that hardware around and would be able to help me with testing? > > Thanks, > > Rajat > {.n + +% lzwm b 맲 r zX \ ) w*jg ݢj/ z ޖ 2 ޙ > & )ߡ a G h j:+v w ٥ ��.n��������+%������w��{.n�����{���"�)�� jg��� �����ݢj����G���� ���j:+v���w�m������w�������h�����٥
