On Fri, Nov 22, 2013 at 05:51:02PM -0700, Bjorn Helgaas wrote: > On Mon, Nov 11, 2013 at 01:26:06PM -0800, Rajat Jain wrote: > > Hello, > > > > >> With my patch, we'd eliminate the 1 second delay and the second line > > >> of output above. If we also want to get rid of the first line > > >> "Unexpected CMD_COMPLETED..." also, that would probably have to be > > >> solved by changing the behavior to assume that CC shall be generated > > >> for every SLOTCTRL register write. > > > > > > I *do* want to get rid of the "Unexpected CMD_COMPLETED" complaint. > > > We shouldn't complain about hardware that is working perfectly fine. > > > I don't know the best way to do that yet. I have found a box with the > > > same hardware that was fixed by 5808639bfa98, so I hope to play with > > > it and figure out something that will work nicely for both scenarios. > > > > Please keep posted :-) > > > > > > > > BTW, can you open a report at bugzilla.kernel.org and attach your > > > "lspci -vvxxx" and dmesg output? When we eventually merge a fix, I'd > > > like to have the details archived somewhere. > > > > Done: > > > > https://bugzilla.kernel.org/show_bug.cgi?id=64821 > > > > Please let me know if you need any help in trying something out - I'd > > be more than keen to help - write code or test. > > What do you think of the patch below? I'm afraid we'll trip over > a few other old parts similar to the 82801H, but I'd rather do that > than penalize the parts that work correctly. > Works nicely as far as I can see. Tested on P2020 and P5040 based systems with IDT 89HPES48H12G2. Tested-by: Guenter Roeck <groeck@xxxxxxxxxxx> Guenter > > PCI: pciehp: Support command completion even with no hotplug hardware > > From: Bjorn Helgaas <bhelgaas@xxxxxxxxxx> > > Commit 5808639bfa98 ("pciehp: fix slow probing") fixed a slow probing > problem on hardware that doesn't conform to the spec, but caused a > similar problem for hardware that *does* conform to the spec. > > Per PCIe 3.0, sec 7.8.10 and 6.7.3.2, any write to Slot Control generates a > hot-plug command. Ports that can accept new commands with no delay can set > the "No Command Completed Support" bit. Otherwise the port must indicate > its completion of the command and readiness to accept a new command with a > "command completed event." > > 5808639bfa98 assumes ports that lack a power controller, power indicator, > attention indicator, and interlock will not generate completion events, > even if they neglect to set "No Command Completed Support." But on ports > that lack those elements and *do* support command completion notification, > it causes: > > Unexpected CMD_COMPLETED. Need to wait for command completed event. > Command not completed in 1000 msec > > and forces us to wait for a 1 second timeout. > > This patch makes the 5808639bfa98 workaround into a quirk that's applied > only to devices known to be broken, currently just Intel 82801H ports. > There are probably other similarly-broken devices that may now probe > slowly, but I don't know how to catch them all without penalizing the > ones that play by the rules. > > Link: https://bugzilla.kernel.org/show_bug.cgi?id=64821 > Reported-by: Rajat Jain <rajatjain@xxxxxxxxxxx> > Signed-off-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx> > --- > drivers/pci/hotplug/pciehp_hpc.c | 39 +++++++++++++++++++++++++++++--------- > 1 file changed, 30 insertions(+), 9 deletions(-) > > diff --git a/drivers/pci/hotplug/pciehp_hpc.c b/drivers/pci/hotplug/pciehp_hpc.c > index 3eea3fdd4b0b..2fd2bd59e07f 100644 > --- a/drivers/pci/hotplug/pciehp_hpc.c > +++ b/drivers/pci/hotplug/pciehp_hpc.c > @@ -881,6 +881,34 @@ static inline void dbg_ctrl(struct controller *ctrl) > ctrl_info(ctrl, "Slot Control : 0x%04x\n", reg16); > } > > +static int pciehp_no_command_complete(struct controller *ctrl) > +{ > + struct pcie_device *dev = ctrl->pcie; > + struct pci_dev *pdev = dev->port; > + u16 vendor, device; > + > + if (NO_CMD_CMPL(ctrl)) > + return 1; > + > + /* > + * Controller should notify on command completion unless the "No > + * Command Completed Support" bit is set. But some hardware does > + * not. See https://bugzilla.kernel.org/show_bug.cgi?id=10751 > + */ > + if (!(POWER_CTRL(ctrl) | ATTN_LED(ctrl) | PWR_LED(ctrl) | EMI(ctrl))) { > + vendor = pdev->vendor; > + device = pdev->device; > + if (vendor == PCI_VENDOR_ID_INTEL && > + device >= 0x283f && device <= 0x2849) { > + dev_info(&dev->device, "device [%04x:%04x] does not notify on hotplug command completion\n", > + vendor, device); > + return 1; > + } > + } > + > + return 0; > +} > + > struct controller *pcie_init(struct pcie_device *dev) > { > struct controller *ctrl; > @@ -902,15 +930,8 @@ struct controller *pcie_init(struct pcie_device *dev) > mutex_init(&ctrl->ctrl_lock); > init_waitqueue_head(&ctrl->queue); > dbg_ctrl(ctrl); > - /* > - * Controller doesn't notify of command completion if the "No > - * Command Completed Support" bit is set in Slot Capability > - * register or the controller supports none of power > - * controller, attention led, power led and EMI. > - */ > - if (NO_CMD_CMPL(ctrl) || > - !(POWER_CTRL(ctrl) | ATTN_LED(ctrl) | PWR_LED(ctrl) | EMI(ctrl))) > - ctrl->no_cmd_complete = 1; > + > + ctrl->no_cmd_complete = pciehp_no_command_complete(ctrl); > > /* Check if Data Link Layer Link Active Reporting is implemented */ > if (pciehp_readl(ctrl, PCI_EXP_LNKCAP, &link_cap)) { > -- > To unsubscribe from this list: send the line "unsubscribe linux-hotplug" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html > > -- 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
