... using the biggest hammer we have. This is essentially a weaponized version of the timeout-based wedging Chris added in
commit 36703e79a982c8ce5a8e43833291f2719e92d0d1 Author: Chris Wilson chris@chris-wilson.co.uk Date: Thu Jun 22 11:56:25 2017 +0100
drm/i915: Break modeset deadlocks on reset
Because defense-in-depth is good it's good to still have both. Also note that with the locking change we can now restrict this a lot (old gpus and special testing only), so this doesn't kill the TDR benefits on at least anything remotely modern.
And futuremore with a few tricks it should be possible to make a much more educated guess about whether an atomic commit is stuck waiting on the gpu (atomic_t counting the pending i915_sw_fence used by the atomic modeset code should do it), so we can improve this.
But for now just start with something that is guaranteed to recover faster, for much better CI througput.
This defacto reverts TDR on these platforms, but there's not really a single commit to specify as the sole offender.
Fixes: 4680816be336 ("drm/i915: Wait first for submission, before waiting for request completion") Fixes: 221fe7994554 ("drm/i915: Perform a direct reset of the GPU from the waiter") Cc: Chris Wilson chris@chris-wilson.co.uk Cc: Mika Kuoppala mika.kuoppala@intel.com Cc: Joonas Lahtinen joonas.lahtinen@linux.intel.com Signed-off-by: Daniel Vetter daniel.vetter@intel.com --- drivers/gpu/drm/i915/intel_display.c | 5 +++++ 1 file changed, 5 insertions(+)
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c index 97777ffa1566..010a1f3e000c 100644 --- a/drivers/gpu/drm/i915/intel_display.c +++ b/drivers/gpu/drm/i915/intel_display.c @@ -3471,6 +3471,11 @@ void intel_prepare_reset(struct drm_i915_private *dev_priv) !gpu_reset_clobbers_display(dev_priv)) return;
+ /* We have a modeset vs reset deadlock, defensively unbreak it. + * + * FIXME: We can do a _lot_ better, this is just a first iteration.*/ + i915_gem_set_wedged(dev_priv); + /* * Need mode_config.mutex so that we don't * trample ongoing ->detect() and whatnot.