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. ~Andrew _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/intel-gfx
