On Thu, 31 Oct 2013, 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. --- 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 -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
