drm/msm: ensure msm_drm probe and eDRM Probe completion

There are issues when display driver probe() execution is scheduled
out during kernel boot because probe_type marked as
PROBE_PREFER_ASYNCHRONOUS.
Since there are few kernel modules that needs display driver to be
initialized. This change adds late_initcall() function which waits
for the completion of probes() to ensure that display is
initialized before other kernel module which can impact the system
boot behavior.

Change-Id: Idd83ac0450ed6f8e09dc98de8bbcec05942302e7
Signed-off-by: Rahul Sharma <rahsha@codeaurora.org>

2 files changed, 29 insertions, 0 deletions

diff --git a/drivers/gpu/drm/msm/ekms/edrm_drv.c b/drivers/gpu/drm/msm/ekms/edrm_drv.c
index 69b8c01e59d4..3711b4680d0a 100644
--- a/drivers/gpu/drm/msm/ekms/edrm_drv.c
+++ b/drivers/gpu/drm/msm/ekms/edrm_drv.c
@@ -23,6 +23,8 @@
 #include "msm_mmu.h"
 #include "edrm_kms.h"
 
+static struct completion wait_display_completion;
+
 static int msm_edrm_unload(struct drm_device *dev)
 {
 	struct msm_drm_private *priv = dev->dev_private;
@@ -367,6 +369,7 @@ static int msm_pdev_edrm_probe(struct platform_device *pdev)
 	if (ret)
 		DRM_ERROR("drm_platform_init failed: %d\n", ret);
 
+	complete(&wait_display_completion);
 	return ret;
 }
 
@@ -423,6 +426,7 @@ static struct platform_driver msm_platform_driver = {
 static int __init msm_edrm_register(void)
 {
 	DBG("init");
+	init_completion(&wait_display_completion);
 	return platform_driver_register(&msm_platform_driver);
 }
 
@@ -432,8 +436,18 @@ static void __exit msm_edrm_unregister(void)
 	platform_driver_unregister(&msm_platform_driver);
 }
 
+static int __init msm_edrm_late_register(void)
+{
+	pr_debug("wait for eDRM display probe completion\n");
+	wait_for_completion(&wait_display_completion);
+
+	return 0;
+}
+
 module_init(msm_edrm_register);
 module_exit(msm_edrm_unregister);
+/* init level 7 */
+late_initcall(msm_edrm_late_register);
 
 MODULE_DESCRIPTION("MSM EARLY DRM Driver");
 MODULE_LICENSE("GPL v2");
diff --git a/drivers/gpu/drm/msm/msm_drv.c b/drivers/gpu/drm/msm/msm_drv.c
index f3df176ce094..f36b992690c4 100644
--- a/drivers/gpu/drm/msm/msm_drv.c
+++ b/drivers/gpu/drm/msm/msm_drv.c
@@ -47,6 +47,8 @@
 #include "msm_gem.h"
 #include "msm_mmu.h"
 
+static struct completion wait_display_completion;
+
 static void msm_drm_helper_hotplug_event(struct drm_device *dev)
 {
 	struct drm_connector *connector;
@@ -2406,6 +2408,7 @@ static int msm_pdev_probe(struct platform_device *pdev)
 		return ret;
 
 	ret = msm_add_master_component(&pdev->dev, match);
+	complete(&wait_display_completion);
 
 	return ret;
 }
@@ -2459,6 +2462,7 @@ static struct platform_driver msm_platform_driver = {
 		.name   = "msm_drm",
 		.of_match_table = dt_match,
 		.pm     = &msm_pm_ops,
+		.probe_type = PROBE_PREFER_ASYNCHRONOUS,
 	},
 	.id_table   = msm_id,
 };
@@ -2481,6 +2485,7 @@ static int __init msm_drm_register(void)
 	msm_edp_register();
 	hdmi_register();
 	adreno_register();
+	init_completion(&wait_display_completion);
 	return platform_driver_register(&msm_platform_driver);
 }
 
@@ -2495,8 +2500,18 @@ static void __exit msm_drm_unregister(void)
 	msm_smmu_driver_cleanup();
 }
 
+static int __init msm_drm_late_register(void)
+{
+	pr_debug("wait for display probe completion\n");
+	wait_for_completion(&wait_display_completion);
+
+	return 0;
+}
+
 module_init(msm_drm_register);
 module_exit(msm_drm_unregister);
+/* init level 7 */
+late_initcall(msm_drm_late_register);
 
 MODULE_AUTHOR("Rob Clark <robdclark@gmail.com");
 MODULE_DESCRIPTION("MSM DRM Driver");