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authorVille Syrjälä <ville.syrjala@linux.intel.com>2020-10-15 13:21:35 +0100
committerRodrigo Vivi <rodrigo.vivi@intel.com>2020-10-19 13:29:47 -0400
commit1664ffee760a5d98952318fdd9b198fae396d660 (patch)
tree7a699640872a0a95a26e82a83c2eb61de02e741d /drivers/gpu
parent849c0fe9e831dcebea1b46e2237e13f274a8756a (diff)
downloadlinux-1664ffee760a5d98952318fdd9b198fae396d660.tar.bz2
drm/i915: Mark ininitial fb obj as WT on eLLC machines to avoid rcu lockup during fbdev init
Currently we leave the cache_level of the initial fb obj set to NONE. This means on eLLC machines the first pin_to_display() will try to switch it to WT which requires a vma unbind+bind. If that happens during the fbdev initialization rcu does not seem operational which causes the unbind to get stuck. To most appearances this looks like a dead machine on boot. Avoid the unbind by already marking the object cache_level as WT when creating it. We still do an excplicit ggtt pin which will rewrite the PTEs anyway, so they will match whatever cache level we set. Cc: <stable@vger.kernel.org> # v5.7+ Suggested-by: Chris Wilson <chris@chris-wilson.co.uk> Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/2381 Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com> Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk> Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Link: https://patchwork.freedesktop.org/patch/msgid/20201007120329.17076-1-ville.syrjala@linux.intel.com Link: https://patchwork.freedesktop.org/patch/msgid/20201015122138.30161-1-chris@chris-wilson.co.uk (cherry picked from commit d46b60a2e8d246f1f0faa38e52f4f5a73858c338) Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Diffstat (limited to 'drivers/gpu')
-rw-r--r--drivers/gpu/drm/i915/display/intel_display.c8
1 files changed, 8 insertions, 0 deletions
diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c
index fac4657a286c..d9494fd7c305 100644
--- a/drivers/gpu/drm/i915/display/intel_display.c
+++ b/drivers/gpu/drm/i915/display/intel_display.c
@@ -3434,6 +3434,14 @@ initial_plane_vma(struct drm_i915_private *i915,
if (IS_ERR(obj))
return NULL;
+ /*
+ * Mark it WT ahead of time to avoid changing the
+ * cache_level during fbdev initialization. The
+ * unbind there would get stuck waiting for rcu.
+ */
+ i915_gem_object_set_cache_coherency(obj, HAS_WT(i915) ?
+ I915_CACHE_WT : I915_CACHE_NONE);
+
switch (plane_config->tiling) {
case I915_TILING_NONE:
break;