Messages in this thread Patch in this message | | | From | David Brownell <> | Subject | Re: [linux-usb-devel] Re: USB 2.0 ehci failure with large amount of RAM (4GB) on x86_64 | Date | Fri, 12 May 2006 21:32:39 -0700 |
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On Tuesday 09 May 2006 10:37 pm, Nathan Becker wrote: > I added 1 line to drivers/usb/host/ehci-pci.c which sets the DMA mask, > and now it seems to work with ehci loaded and with 4 GB of RAM. > Unfortunately, I don't really understand what I did. Perhaps you have > a better idea what this is doing and if it is correct.
Interesting. My guess is that the IOMMU is helping you out, and the issue is that the silicon erratum applies to the I/O buffers too, not just to a subset of the schedule data structures.
Can you confirm that this patch also resolves your issue? Reboot from scratch a few times (power off, warm reboot, etc) to be reasonably sure you're seeing the cases that failed before.
Modify workaround for the EHCI quirk in newer NVidia controllers by assigning the DMA mask, not just the consistent DMA mask. It seems to matter, as if the silicon erratum isn't quite what was described in the original bug workaround (or there's another erratum).
Index: g26/drivers/usb/host/ehci-pci.c =================================================================== --- g26.orig/drivers/usb/host/ehci-pci.c 2006-05-12 19:40:22.000000000 -0700 +++ g26/drivers/usb/host/ehci-pci.c 2006-05-12 21:15:31.000000000 -0700 @@ -118,7 +118,15 @@ static int ehci_pci_setup(struct usb_hcd if (pci_set_consistent_dma_mask(pdev, DMA_31BIT_MASK) < 0) ehci_warn(ehci, "can't enable NVidia " - "workaround for >2GB RAM\n"); + "workaround %d for >2GB RAM\n", 1); + + /* some users report problems with 4GB when the IOMMU + * doesn't force lowmem addresses... looks like the + * initial report from NVidia wasn't quite right. + */ + if (pci_set_dma_mask(pdev, DMA_31BIT_MASK) < 0) + ehci_warn(ehci, "can't enable NVidia " + "workaround %d for >2GB RAM\n", 2); break; /* Some NForce2 chips have problems with selective suspend; * fixed in newer silicon. | |