CVSROOT: /cvs
Module name: src
Changes by: j...@cvs.openbsd.org 2021/06/04 05:21:08
Modified files:
sys/dev/pci/drm/i915: Tag: OPENBSD_6_8 i915_pci.c
Log message:
disable ppgtt on cherryview/braswell
With ppgtt enabled the contents of struct gen6_ppgtt are overwritten
leading to unexpected values for vma pointer such as 0 and 1.
Multiple people have reported problems with 6.9 on cherryview/braswell
with traces along the lines of
uvm_fault(0xffffffff8214ea68, 0xb8, 0, 1) -> e
kernel: page fault trap, code=0
Stopped at i915_ggtt_pin+0x29: movq 0xb8(%rdi),%r12
i915_ggtt_pin(0,10000,20) at i915_ggtt_pin+0x29
gen6_ppgtt_pin(ffff800000cb9400) at gen6_ppgtt_pin+0x7c
__intel_context_do_pin(fffffd817dc8ad80) at __intel_context_do_pin+0xca
intel_engines_init(ffff800000104c38) at intel_engines_init+0x4b5
intel_gt_init(ffff800000104c38) at intel_gt_init+0x130
i915_gem_init(ffff800000100000) at i915_gem_init+0xa3
i915_driver_probe(ffff800000100000,ffffffff81fc6e90) at i915_driver_probe+0x7ed
The "use drm_mm from linux 5.7.y" commit made last October is
implicated in the change in behaviour but does not itself have any
cherryview/braswell specific changes. There is at least one report on
misc@ which suggests this occurred in some situations with 6.8 which
lacks that change.
Thanks to the people who reported this in particular Matthias Pressfreund
who tested many patches.
this is errata/6.8/024_inteldrm.patch.sig
