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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