From 636352173a0dd127636fe331c97b117a8004bf50 Mon Sep 17 00:00:00 2001 From: Paulo Zanoni Date: Tue, 22 Apr 2014 19:55:42 -0300 Subject: [PATCH] drm/i915: get power domain in case the BIOS enabled eDP VDD If I unplug the eDP monitor, the BIOS of my machine will enable the VDD bit, then when the driver loads it will think VDD is enabled. It will detect that the eDP is not enabled and return false from intel_edp_init_connector. This will trigger a call to edp_panel_vdd_off_sync(), which trigger a WARN saying that the refcount of the power domain is less than zero. The problem happens because the driver gets a refcount whenever it enables the VDD bit, and puts the refcount whenever it disables the VDD bit. But on this case, the BIOS enabled VDD, so all we do is to call put() without calling get() first, so the code added is there to make sure we always have the get() in case the BIOS enabled the bit. This regression was introduced in commit e9cb81a22841908b1c075156b409a538d09c8466 Author: Paulo Zanoni Date: Thu Nov 21 13:47:23 2013 -0200 drm/i915: get a runtime PM reference when the panel VDD is on v2: - Rebase Tested-by: Chris Wilson (v1) Reviewed-by: Daniel Vetter Cc: stable@vger.kernel.org (v3.13+) Signed-off-by: Paulo Zanoni Signed-off-by: Jani Nikula --- drivers/gpu/drm/i915/intel_dp.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c index d2a55884ad52..dfa85289f28f 100644 --- a/drivers/gpu/drm/i915/intel_dp.c +++ b/drivers/gpu/drm/i915/intel_dp.c @@ -3619,7 +3619,8 @@ static bool intel_edp_init_connector(struct intel_dp *intel_dp, { struct drm_connector *connector = &intel_connector->base; struct intel_digital_port *intel_dig_port = dp_to_dig_port(intel_dp); - struct drm_device *dev = intel_dig_port->base.base.dev; + struct intel_encoder *intel_encoder = &intel_dig_port->base; + struct drm_device *dev = intel_encoder->base.dev; struct drm_i915_private *dev_priv = dev->dev_private; struct drm_display_mode *fixed_mode = NULL; bool has_dpcd; @@ -3629,6 +3630,14 @@ static bool intel_edp_init_connector(struct intel_dp *intel_dp, if (!is_edp(intel_dp)) return true; + /* The VDD bit needs a power domain reference, so if the bit is already + * enabled when we boot, grab this reference. */ + if (edp_have_panel_vdd(intel_dp)) { + enum intel_display_power_domain power_domain; + power_domain = intel_display_port_power_domain(intel_encoder); + intel_display_power_get(dev_priv, power_domain); + } + /* Cache DPCD and EDID for edp. */ intel_edp_panel_vdd_on(intel_dp); has_dpcd = intel_dp_get_dpcd(intel_dp); -- 2.20.1