From 6fa9a5ecf7a54450b255229ac1fc6df276cf0653 Mon Sep 17 00:00:00 2001
From: Imre Deak <imre.deak@intel.com>
Date: Fri, 12 Feb 2016 18:55:18 +0200
Subject: [PATCH] drm/i915/dp: Ensure the HW is powered during HW state readout
The assumption when adding the intel_display_power_is_enabled() checks
was that if it returns success the power can't be turned off afterwards
during the HW access, which is guaranteed by modeset locks. This isn't
always true, so make sure we hold a dedicated reference for the time of
the access.
Signed-off-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1455296121-4742-10-git-send-email-imre.deak@intel.com
---
drivers/gpu/drm/i915/intel_dp.c | 18 ++++++++++++++----
1 file changed, 14 insertions(+), 4 deletions(-)
diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index a48c4290552e..f6e4a87a9892 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -2369,15 +2369,18 @@ static bool intel_dp_get_hw_state(struct intel_encoder *encoder,
struct drm_i915_private *dev_priv = dev->dev_private;
enum intel_display_power_domain power_domain;
u32 tmp;
+ bool ret;
power_domain = intel_display_port_power_domain(encoder);
- if (!intel_display_power_is_enabled(dev_priv, power_domain))
+ if (!intel_display_power_get_if_enabled(dev_priv, power_domain))
return false;
+ ret = false;
+
tmp = I915_READ(intel_dp->output_reg);
if (!(tmp & DP_PORT_EN))
- return false;
+ goto out;
if (IS_GEN7(dev) && port == PORT_A) {
*pipe = PORT_TO_PIPE_CPT(tmp);
@@ -2388,7 +2391,9 @@ static bool intel_dp_get_hw_state(struct intel_encoder *encoder,
u32 trans_dp = I915_READ(TRANS_DP_CTL(p));
if (TRANS_DP_PIPE_TO_PORT(trans_dp) == port) {
*pipe = p;
- return true;
+ ret = true;
+
+ goto out;
}
}
@@ -2400,7 +2405,12 @@ static bool intel_dp_get_hw_state(struct intel_encoder *encoder,
*pipe = PORT_TO_PIPE(tmp);
}
- return true;
+ ret = true;
+
+out:
+ intel_display_power_put(dev_priv, power_domain);
+
+ return ret;
}
static void intel_dp_get_config(struct intel_encoder *encoder,