[PATCH] drm/msm/hdmi: handle runtime resume failure during power on

[Jiale Yao]

msm_hdmi_power_on() ignores runtime resume failures, and
atomic_pre_enable then records the bridge as powered and accesses HDMI
registers. The later disable path also drops a runtime PM reference
that was not acquired.

Return the resume error to atomic_pre_enable, unwind the PHY resources,
and stop the enable sequence without setting power_on. Also honor
errors from the preceding PHY resource enable operation so the unwind
is only used after successful acquisition.

Fixes: 81aa83419706 ("drm/msm/hdmi: switch to pm_runtime_resume_and_get()")
Signed-off-by: Jiale Yao <yaojial...@163.com>
---
 drivers/gpu/drm/msm/hdmi/hdmi_bridge.c | 26 ++++++++++++++++++++++----
 1 file changed, 22 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/msm/hdmi/hdmi_bridge.c 
b/drivers/gpu/drm/msm/hdmi/hdmi_bridge.c
index 157f19bd90b4..7d88657be047 100644
--- a/drivers/gpu/drm/msm/hdmi/hdmi_bridge.c
+++ b/drivers/gpu/drm/msm/hdmi/hdmi_bridge.c
@@ -13,14 +13,16 @@
 #include "msm_kms.h"
 #include "hdmi.h"
 
-static void msm_hdmi_power_on(struct drm_bridge *bridge)
+static int msm_hdmi_power_on(struct drm_bridge *bridge)
 {
        struct drm_device *dev = bridge->dev;
        struct hdmi_bridge *hdmi_bridge = to_hdmi_bridge(bridge);
        struct hdmi *hdmi = hdmi_bridge->hdmi;
        int ret;
 
-       pm_runtime_resume_and_get(&hdmi->pdev->dev);
+       ret = pm_runtime_resume_and_get(&hdmi->pdev->dev);
+       if (ret < 0)
+               return ret;
 
        if (hdmi->extp_clk) {
                DBG("pixclock: %lu", hdmi->pixclock);
@@ -32,6 +34,8 @@ static void msm_hdmi_power_on(struct drm_bridge *bridge)
                if (ret)
                        DRM_DEV_ERROR(dev->dev, "failed to enable extp clk: 
%d\n", ret);
        }
+
+       return 0;
 }
 
 static void power_off(struct drm_bridge *bridge)
@@ -276,6 +280,7 @@ static void msm_hdmi_bridge_atomic_pre_enable(struct 
drm_bridge *bridge,
        struct drm_connector *connector;
        struct drm_connector_state *conn_state;
        struct drm_crtc_state *crtc_state;
+       int ret;
 
        DBG("power up");
 
@@ -289,8 +294,16 @@ static void msm_hdmi_bridge_atomic_pre_enable(struct 
drm_bridge *bridge,
 
        mutex_lock(&hdmi->state_mutex);
        if (!hdmi->power_on) {
-               msm_hdmi_phy_resource_enable(phy);
-               msm_hdmi_power_on(bridge);
+               ret = msm_hdmi_phy_resource_enable(phy);
+               if (ret)
+                       goto unlock;
+
+               ret = msm_hdmi_power_on(bridge);
+               if (ret) {
+                       msm_hdmi_phy_resource_disable(phy);
+                       goto unlock;
+               }
+
                hdmi->power_on = true;
        }
        mutex_unlock(&hdmi->state_mutex);
@@ -306,6 +319,11 @@ static void msm_hdmi_bridge_atomic_pre_enable(struct 
drm_bridge *bridge,
 
        if (hdmi->hdcp_ctrl)
                msm_hdmi_hdcp_on(hdmi->hdcp_ctrl);
+
+       return;
+
+unlock:
+       mutex_unlock(&hdmi->state_mutex);
 }
 
 static void msm_hdmi_bridge_atomic_post_disable(struct drm_bridge *bridge,
-- 
2.34.1