Disabling HPD polling from i915_hpd_poll_init_work() involves probing all display connectors explicitly to account for lost hotplug interrupts. On some platforms (mostly pre-ICL) with HDMI connectors the I2C EDID bit-banging using udelay() triggers in turn the

workqueue: i915_hpd_poll_init_work [i915] hogged CPU for >10000us 4 times, consider switching to WQ_UNBOUND

warning.

Fix the above by scheduling i915_hpd_poll_init_work() on a WQ_UNBOUND workqueue. It's ok to use a system WQ, since i915_hpd_poll_init_work() is properly flushed in intel_hpd_cancel_work().

The connector probing from drm_mode_config::output_poll_work resulting in the same warning is fixed by the next patch.

Cc: Tejun Heo tj@kernel.org Cc: Heiner Kallweit hkallweit1@gmail.com CC: stable@vger.kernel.org # 6.5 Suggested-by: Tejun Heo tj@kernel.org Suggested-by: Heiner Kallweit hkallweit1@gmail.com Reported-by: Heiner Kallweit hkallweit1@gmail.com Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/9245 Link: https://lore.kernel.org/all/f7e21caa-e98d-e5b5-932a-fe12d27fde9b@gmail.com Signed-off-by: Imre Deak imre.deak@intel.com --- drivers/gpu/drm/i915/display/intel_hotplug.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_hotplug.c b/drivers/gpu/drm/i915/display/intel_hotplug.c index e8562f6f8bb44..accc2fec562a0 100644 --- a/drivers/gpu/drm/i915/display/intel_hotplug.c +++ b/drivers/gpu/drm/i915/display/intel_hotplug.c @@ -774,7 +774,7 @@ void intel_hpd_poll_enable(struct drm_i915_private *dev_priv) * As well, there's no issue if we race here since we always reschedule * this worker anyway */ - queue_work(dev_priv->unordered_wq, + queue_work(system_unbound_wq, &dev_priv->display.hotplug.poll_init_work); }

@@ -803,7 +803,7 @@ void intel_hpd_poll_disable(struct drm_i915_private *dev_priv) return;

WRITE_ONCE(dev_priv->display.hotplug.poll_enabled, false); - queue_work(dev_priv->unordered_wq, + queue_work(system_unbound_wq, &dev_priv->display.hotplug.poll_init_work); }