On Tue, 3 Jun 2014, Bjorn Helgaas wrote: > >>> > Attached is dmesg output leading to timeouts (that are cured by my > >>> > original patch in this thread) and lspci. > >>> > >>> I opened https://bugzilla.kernel.org/show_bug.cgi?id=64141 for this > >>> issue and attached your dmesg log and lspci output. > >>> > >>> > Please let me know if there is anything else I could do, or if you are > >>> > going to proceed with my patch adding the quirk. > >>> > >>> Your quirk keeps us from disabling MSIs on the device during > >>> enumeration. But even if the BIOS left MSIs enabled, there's nothing > >>> to field the MSI until after the driver claims the device. So I don't > >>> believe this has to be done as a quirk. It should work just as well > >>> to do something in the driver when it claims the device. > >>> > >>> I guess another way to say this is that I don't think we understand > >>> what the real problem is, and if we just add a quirk to work around > >>> it, we might miss the chance to fix the real problem, and we may never > >>> be able to remove the special-case code we're adding in the generic > >>> path. > >>> > >>> I know you said you tried doing something in the driver, and it didn't > >>> work. I don't know exactly what you tried, but twa_probe() looks > >>> strange to me. The other drivers I looked at do all their PCI > >>> initialization before the scsi_host_alloc() / scsi_add_host() / > >>> scsi_scan_host() stuff. But twa_probe() has PCI stuff scattered > >>> around between those three SCSI calls. In particular, it does the MSI > >>> setup way down near the end, after scsi_add_host(), which seems like > >>> just the sort of thing that could explain this problem. > >> > >> What I tried was patch below, but it didn't have any observable effect -- > >> the commands sent to the controller would still time out the same way. > >> > >> Debugging this is not really straightforward for me unfortunately, as I > >> don't own the system myself. > >> > >> I agree that we don't fully understand what is happening, but the quirk > >> was the only way I have been able to come up with to make the device > >> functioning again (apart from reverting d5dea7d95). > >> > >> Any other ideas are welcome. > > > > This patch looks like a good start, but there's a whole lot of other > > PCI-related initialization that I would suggest moving as well -- > > pci_request_regions(), ioremap(), pci_set_drvdata(), pci_enable_msi, > > request_irq(), etc. I would do this myself, but there are some pieces > > that don't look completely trivial, e.g., things like > > TW_DISABLE_INTERRUPTS() and twa_reset_sequence() don't look like > > they're SCSI-specific, but they are currently implemented using > > tw_dev, which looks like it's allocated by scsi_host_alloc(). > > Untangling all this looks like more work than I want to sign up to. > > > > But I really don't want to put the quirk in because it's just a quick > > hack that apparently just covers up bugs in the driver, and it will be > > an annoyance in the PCI core forever. > > Just FYI, I reassigned > https://bugzilla.kernel.org/show_bug.cgi?id=64141 from PCI to SCSI, > since I don't think there's a PCI core problem here. I don't know if > SCSI pay attention to bugzilla at all; I'm just mentioning it here in > case anybody still cares about this problem and was hoping that I was > going to do something. I am adding to CC Ales Novak, who has been handling this bug on our side lately. > > Bjorn > > >> --- > >> drivers/scsi/3w-9xxx.c | 10 +++++----- > >> 1 files changed, 5 insertions(+), 5 deletions(-) > >> > >> diff --git a/drivers/scsi/3w-9xxx.c b/drivers/scsi/3w-9xxx.c > >> index ba754c3..bad7faf 100644 > >> --- a/drivers/scsi/3w-9xxx.c > >> +++ b/drivers/scsi/3w-9xxx.c > >> @@ -2055,6 +2055,11 @@ static int __devinit twa_probe(struct pci_dev *pdev, const struct pci_device_id > >> goto out_disable_device; > >> } > >> > >> + /* Try to enable MSI */ > >> + if (use_msi && (pdev->device != PCI_DEVICE_ID_3WARE_9000) && > >> + !pci_enable_msi(pdev)) > >> + set_bit(TW_USING_MSI, &tw_dev->flags); > >> + > >> host = scsi_host_alloc(&driver_template, sizeof(TW_Device_Extension)); > >> if (!host) { > >> TW_PRINTK(host, TW_DRIVER, 0x24, "Failed to allocate memory for device extension"); > >> @@ -2134,11 +2139,6 @@ static int __devinit twa_probe(struct pci_dev *pdev, const struct pci_device_id > >> le32_to_cpu(*(int *)twa_get_param(tw_dev, 2, TW_INFORMATION_TABLE, > >> TW_PARAM_PORTCOUNT, TW_PARAM_PORTCOUNT_LENGTH))); > >> > >> - /* Try to enable MSI */ > >> - if (use_msi && (pdev->device != PCI_DEVICE_ID_3WARE_9000) && > >> - !pci_enable_msi(pdev)) > >> - set_bit(TW_USING_MSI, &tw_dev->flags); > >> - > >> /* Now setup the interrupt handler */ > >> retval = request_irq(pdev->irq, twa_interrupt, IRQF_SHARED, "3w-9xxx", tw_dev); > >> if (retval) { > >> > >> > >> -- > >> Jiri Kosina > >> SUSE Labs > -- Jiri Kosina SUSE Labs -- 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
