Messages in this thread | | | Date | Sat, 19 Jan 2013 15:47:53 +0100 | From | dAgeCKo <> | Subject | Re: Fwd: Linux - AMD SB950 USB Regression |
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Le 17/01/2013 22:36, Borislav Petkov a écrit :
> > So, there seems to be some serious breakage with GART on SB9xx. I don't > know whether this is the platform BIOS or the vendor BIOS causing it > because the original bug reporter says he observes the issue on an MSI > board and I'm experiencing this on my favourite bunch ASUS. > > So, if you use the GART as an IOMMU, i.e.: > > Jan 17 22:08:15 pd kernel: [ 0.924063] PCI-DMA: using GART IOMMU. > Jan 17 22:08:15 pd kernel: [ 0.924120] PCI-DMA: Reserving 64MB of IOMMU area in the AGP aperture > > USB ports start choking like this: > > Jan 17 22:08:15 pd kernel: [ 3.229909] usb 4-1: device descriptor read/64, error -32 > Jan 17 22:08:15 pd kernel: [ 3.432786] usb 4-1: new high-speed USB device number 3 using ehci-pci > Jan 17 22:08:15 pd kernel: [ 3.534684] usb 4-1: device descriptor read/64, error -32 > Jan 17 22:08:15 pd kernel: [ 3.737642] usb 4-1: device descriptor read/64, error -32
Yes, this is exactly what I faced.
> > I'd go and venture a guess here since I don't have an idea that DMA > somehow gets busted with the GART and thus the errors. > > Now, those boards normally have an IOMMU too so if you go and enable > > CONFIG_AMD_IOMMU=y > > the problem is gone (we're using the real IOMMU for DMA mapping, etc, > etc). So dAgeCKo, that would be another thing you could do: try enabling > the IOMMU in the BIOS and the above CONFIG option and the issue would be > fixed too.
Here is below, exactly what the guy from MSI said me after I said him a BIOS upgrade did resolve my bug:
"The reacts differently to Win/Linux, but it relies on updates by AMD. The new AGESA in the BIOS might had fixes for Linux."
After few researches, it seems that this "BIOS-level" software has effectively a special implementation wrapper for Linux (something I can't understand why actually). For more reference you can find little information here (http://www.coreboot.org/data/LinuxBIOS%20AMD%202006%20Final_10-02-2006.pdf).
I can't try the solution you are giving since I can't (and don't want to try to) downgrade my BIOS.
Another important thing you might be interested in is that not only my USB 2 weren't working. My mainboard ethernet wasn't working to (and was resolved with the BIOS upgrade too). The ethernet chip is:
03:00.0 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL8111/8168B PCI Express Gigabit Ethernet controller (rev 06)
I don't know if that can be related to what you are saying.
> > At least this fixes it on my box. > > To the question "how do we fix the GART issue?" I have no answer and > would expect more informed opinions from someone else.
Actually I can't tell if I have any GART issues. The only thing I can say is that 3D looks to work nicely. However I think I never consumed more memory than my graphic card has.
> > Thanks and HTH. >
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