Hello, On Wed, Feb 12, 2014 at 8:56 AM, Bjorn Helgaas <bhelgaas@xxxxxxxxxx> wrote: > On Wed, Feb 12, 2014 at 1:00 AM, Izumi, Taku <izumi.taku@xxxxxxxxxxxxxx> wrote: >> Hi Bjorn, >> >>> Hi Taku, >>> >>> Thanks a lot for finding and bisecting this problem. I recently merged >>> some patches from Rajat that partially revert 2debd9289997. Can you try >>> out my pci/pciehp branch and see whether it is enough to fix the problem >>> for you? >>> >>> Here's the branch: >>> http://git.kernel.org/cgit/linux/kernel/git/helgaas/pci.git/log/?h=pci/pciehp >>> >>> and the specific change Rajat made is: >>> http://git.kernel.org/cgit/linux/kernel/git/helgaas/pci.git/commit/?h=pci/pciehp&id=b1811d2455f32754cc3d8725bf2e961c >>> 5eda2a72 >>> >>> Let me know if that isn't enough to fix the problem you're seeing, and we >>> can work on it some more. >> >> I tested the kernel checkouted from remotes/origin/pci/pciehp. >> The original problem I reported was fixed. >> However the sequence of hot-plug operation got changed. >> The slot power becomes ON the moment when I insert PCIe card on the slot. >> This behavior is unacceptable to me. >> >> (before) >> - hot-add >> 1. insert PCIe card >> 2. echo 1 > power >> - hot-remove >> 1. echo 0 > power >> 2. eject PCIe card >> >> (after) >> - hot-add >> 1. insert PCIe card (and automatically power-on) >> >> - hot-remove >> 1. echo 0 > power >> 2. eject PCIe card > > Huh, that doesn't sound good. Does your slot have an attention > button? Can you collect the "lspci -vvv" output for the Downstream > Port leading to this slot? If there is no attention button, then the behavior seen, matches with what I expected of the code. Seemingly, the HW does not have a power controller (and attention button), thus the power is automatically turned on (by HW) when card is inserted and the link comes up. Thus prior to link state based hot-plug, "echo 1 > power" used to do a little else than initiate a rescan for this particular HW. > > I think that for ExpressCard and similar devices, we want to turn on > the device and attach a driver as soon as the card is inserted. But > in your case, I assume we want a model like that in Table 2-7 of the > "PCI Standard Hot-Plug Controller and Subsystem Specification," rev > 1.0, i.e., "Hot Insertion Initiated via Software UI." So there must > be some way to differentiate an ExpressCard slot from a slot like > yours. Yes, that would help if there was some way. Thanks, Rajat > > Bjorn -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
