On Fri, Aug 15, 2014 at 03:05:39PM -0700, Yinghai Lu wrote: > On Sat, Jun 14, 2014 at 2:21 PM, Bjorn Helgaas <bhelgaas@xxxxxxxxxx> wrote: > > Yinghai has been working on pciehp timeouts related to a hardware > > erratum in Intel, AMD, and Nvidia hotplug controllers. This affects > > the way we wait for command completion on those controllers. > > > > I had some suggestions about how to change pciehp to make this work > > better in general, without having to check for specific vendors. We > > need something that works well on hardware that conforms to the spec, > > as well as the stuff that doesn't. > > > > I haven't heard anything for a while, so I wrote up these patches to > > make my proposals concrete. Unfortunately, I can't easily test any of > > this, so I'm posting these for comment and possible testing if anybody > > is ambitious. > > > > The Intel erratum is CF118, described here: > > http://www.intel.com/content/www/us/en/processors/xeon/xeon-e7-v2-spec-update.html > > --- > > > > Bjorn Helgaas (4): > > PCI: pciehp: Make pcie_wait_cmd() self-contained > > PCI: pciehp: Wait for hotplug command completion lazily > > PCI: pciehp: Compute timeout from hotplug command start time > > PCI: pciehp: Remove assumptions about which commands cause completion events > > > > > > drivers/pci/hotplug/pciehp.h | 2 + > > drivers/pci/hotplug/pciehp_hpc.c | 91 +++++++++++++++++--------------------- > > 2 files changed, 42 insertions(+), 51 deletions(-) > > Looks like we missed something. With last kernel I still saw the 1s > delay per slot. > > After adding more debug printout patches, I got following: > > [ 67.476898] calling pcied_init+0x0/0x74 @ 1 > [ 67.477114] pciehp 0000:00:02.0:pcie04: Hotplug Controller: > [ 67.477115] pciehp 0000:00:02.0:pcie04: Seg/Bus/Dev/Func/IRQ : > 0000:00:02.0 IRQ 58 > [ 67.477117] pciehp 0000:00:02.0:pcie04: Vendor ID : 0x8086 > [ 67.477118] pciehp 0000:00:02.0:pcie04: Device ID : 0x2f04 > [ 67.477119] pciehp 0000:00:02.0:pcie04: Subsystem ID : 0x0000 > [ 67.477120] pciehp 0000:00:02.0:pcie04: Subsystem Vendor ID : 0x8086 > [ 67.477121] pciehp 0000:00:02.0:pcie04: PCIe Cap offset : 0x90 > [ 67.477124] pciehp 0000:00:02.0:pcie04: PCI resource [13] : > [io 0x5000-0x5fff] > [ 67.477125] pciehp 0000:00:02.0:pcie04: PCI resource [14] : > [mem 0x98000000-0x9bffffff] > [ 67.477127] pciehp 0000:00:02.0:pcie04: PCI resource [15] : > [mem 0x381800000000-0x381bffffffff 64bit pref] > [ 67.477128] pciehp 0000:00:02.0:pcie04: Slot Capabilities : 0x00088cdb > [ 67.477129] pciehp 0000:00:02.0:pcie04: Physical Slot Number : 1 > [ 67.477130] pciehp 0000:00:02.0:pcie04: Attention Button : yes > [ 67.477131] pciehp 0000:00:02.0:pcie04: Power Controller : yes > [ 67.477132] pciehp 0000:00:02.0:pcie04: MRL Sensor : no > [ 67.477132] pciehp 0000:00:02.0:pcie04: Attention Indicator : yes > [ 67.477133] pciehp 0000:00:02.0:pcie04: Power Indicator : yes > [ 67.477134] pciehp 0000:00:02.0:pcie04: Hot-Plug Surprise : no > [ 67.477135] pciehp 0000:00:02.0:pcie04: EMI Present : no > [ 67.477136] pciehp 0000:00:02.0:pcie04: Command Completed : yes > [ 67.477137] pciehp 0000:00:02.0:pcie04: Slot Status : 0x0010 > [ 67.477138] pciehp 0000:00:02.0:pcie04: Slot Control : 0x07cb > [ 67.477140] pciehp 0000:00:02.0:pcie04: Link Active Reporting supported > [ 67.477144] pciehp 0000:00:02.0:pcie04: pcie_disable_notification: > SLOTCTRL a8 write cmd 0 > [ 67.477145] pciehp 0000:00:02.0:pcie04: Slot #1 AttnBtn+ AttnInd+ > PwrInd+ PwrCtrl+ MRL- Interlock- NoCompl- LLActRep+ > [ 67.479926] pciehp 0000:00:02.0:pcie04: Registering > domain:bus:dev=0000:01:00 sun=1 > [ 67.479975] pci_bus 0000:01: dev 00, created physical slot 1 > [ 67.480041] pci_hotplug: __pci_hp_register: Added slot 1 to the list > [ 69.078753] pciehp 0000:00:02.0:pcie04: Timeout on hotplug command > 0x000007c0 (issued 1604 msec ago) > [ 69.078758] pciehp 0000:00:02.0:pcie04: pcie_enable_notification: > SLOTCTRL a8 write cmd 1031 > [ 69.078763] pciehp 0000:00:02.0:pcie04: pciehp_get_power_status: > SLOTCTRL a8 value read 17f1 > [ 69.078765] pciehp 0000:00:02.0:pcie04: service driver pciehp loaded > > so there are pcie_disable_notification and pcie_enable_notification. > > pcie_enable_notification will wait 1s. > > wonder if we can just remove pcie_disable_notification calling from > pciehp_hpc.c::pcie_init() at all. Yes, I agree. I think it looks safe to drop the pcie_disable_notification() call from pcie_init(). 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
