Hi Joerg, On 01/03/2011 12:29 PM, Roedel, Joerg wrote: > On Tue, Dec 28, 2010 at 08:00:12PM -0500, Jeff Garzik wrote: >> (CC'd linux-ide, Joerg) >> >> On 12/28/2010 06:43 PM, Steffen Moser wrote: >> > I've encountered a problem with my AMD 890FX based system >> > and linux-2.6.35.10 (x86_64 platform). >> > >> > After activating the option "IOMMU" in the mainboard's BIOS >> > setup, the onboard P-ATA controller "JMicron Technology Corp. >> > JMB361 AHCI/IDE (rev 02)" puts itself back in the PIO mode. >> > When loading the module, the kernel reports: >> > >> > pata_jmicron 0000:06:00.1: BMDMA: failed to set dma mask, \ >> > falling back to PIO >> [...] >> > As soon as I deactivate IOMMU in BIOS setup, the P-ATA channel >> > runs in the DMA mode again. The S-ATA controllers don't seem >> > to be affected. >> > >> > My question is: Is this a known behavior? Are there any >> > things I have to consider when activating IOMMU (which seems >> > to be AMD-Vi) on an 890FX based system? Is it a problem of >> > the chipset and/or the controller or is it related to a >> > problem in the libata area? >> > >> > Some information about the affected system: >> > >> > - Mainboard: ASUS M4A89TD Pro/USB3 >> > - BIOS version: 1101 (most recent version) >> > - Chipset: AMD 890FX >> > - Processor: AMD Phenom 1090T >> > - Memory: 4 x 4 GB (Kingston KVR1333D3E9S/4G) >> > - Distribution: openSUSE 11.3 >> > - Kernel: 2.6.35.10 (from "kernel.org"), x86_64 >> > >> >> This condition occurs when the PCI API cannot set the PCI device's DMA >> mask to the 32-bit value >> #define ATA_DMA_MASK 0xffffffffULL >> >> That is an unusual failure for such a modern system, which certainly can >> handle 32-bit masks like that, one would think. > > Luckily I have exactly the same motherboard under my desk. It shows the > same issue. The problem is that the PCI device of the PATA controler > (4:00.1 in my case) is not described in the IVRS ACPI table. So the > IOMMU driver does not feel responsible for it and the dma_supported() > call on this device will fail. This also makes pci_set_dma_mask() fail > on this device. So it comes down to a BIOS bug. That sounds quite comprehensible for me. > I look into it to find a workaround. Thank you. Beside a possible work-around, do you think, it makes sense to report the problem to ASUS as the straight way should be to have a correct IVRS table for the board? Kind regards, Steffen -- To unsubscribe from this list: send the line "unsubscribe linux-ide" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
