On Wed, Oct 14, 2020 at 08:37:06PM +0100, Andrew Cooper wrote: > On 14/10/2020 20:28, Jason Andryuk wrote: > > Hi, > > > > Bug opened at https://gitlab.freedesktop.org/drm/intel/-/issues/2576 > > > > I'm seeing DMA faults for the i915 graphics hardware on a Dell > > Latitude 5500. These were captured when I plugged into a Dell > > Thunderbolt dock with two DisplayPort monitors attached. Xen 4.12.4 > > staging and Linux 5.4.70 (and some earlier versions). > > > > Oct 14 18:41:49.056490 kernel:[ 85.570347] [drm:gen8_de_irq_handler > > [i915]] *ERROR* Fault errors on pipe A: 0x00000080 > > Oct 14 18:41:49.056494 kernel:[ 85.570395] [drm:gen8_de_irq_handler > > [i915]] *ERROR* Fault errors on pipe A: 0x00000080 > > Oct 14 18:41:49.056589 VM hypervisor: (XEN) [VT-D]DMAR:[DMA Read] > > Request device [0000:00:02.0] fault addr 39b5845000, iommu reg = > > ffff82c00021d000 > > Oct 14 18:41:49.056594 VM hypervisor: (XEN) [VT-D]DMAR: reason 06 - > > PTE Read access is not set > > Oct 14 18:41:49.056784 kernel:[ 85.570668] [drm:gen8_de_irq_handler > > [i915]] *ERROR* Fault errors on pipe A: 0x00000080 > > Oct 14 18:41:49.056789 kernel:[ 85.570687] [drm:gen8_de_irq_handler > > [i915]] *ERROR* Fault errors on pipe A: 0x00000080 > > Oct 14 18:41:49.056885 VM hypervisor: (XEN) [VT-D]DMAR:[DMA Read] > > Request device [0000:00:02.0] fault addr 4238d0a000, iommu reg = > > ffff82c00021d000 > > Oct 14 18:41:49.056890 VM hypervisor: (XEN) [VT-D]DMAR: reason 06 - > > PTE Read access is not set > > > > They repeat. In the log attached to > > https://gitlab.freedesktop.org/drm/intel/-/issues/2576, they start at > > "Oct 14 18:41:49.056589" and continue until I unplug the dock around > > "Oct 14 18:41:54.801802". > > > > I've also seen similar messages when attaching the laptop's HDMI port > > to a 4k monitor. The eDP display by itself seems okay. > > > > I tried Fedora 31 & 32 live images with intel_iommu=on, so no Xen, and > > didn't see any errors > > > > This is a kernel & xen log with drm.debug=0x1e. It also includes some > > application (glass) logging when it changes resolutions which seems to > > set off the DMA faults. 5500-igfx-messages-kern-xen-glass > > > > Running xen with iommu=no-igfx disables the iommu for the i915 > > graphics and no faults are reported. However, that breaks some other > > devices (Dell Latitude 7200 and 5580) giving a black screen with: > > > > Oct 10 13:24:37.022117 kernel:[ 14.884759] i915 0000:00:02.0: Failed > > to idle engines, declaring wedged! > > Oct 10 13:24:37.022118 kernel:[ 14.964794] i915 0000:00:02.0: Failed > > to initialize GPU, declaring it wedged! > > > > Any suggestions welcome. > > Presumably this is with a PV dom0. What are 39b5845000 and 4238d0a000 > in the machine memory map? > > This smells like a missing RMRR in the ACPI tables. I agree. Can you paste the memory map as printed by Xen when booting, and what command line are you using to boot Xen. Have you tried adding dom0-iommu=map-inclusive to the Xen command line? Roger. _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/intel-gfx
