[PATCH] drm/msm: properly add and remove internal bridges

[PATCH] drm/msm: properly add and remove internal bridges

[Dmitry Baryshkov]

Add calls to drm_bridge_add()/drm_bridge_remove() DRM bridges created by
the driver. This fixes the following warning.

WARNING: CPU: 0 PID: 1 at kernel/locking/mutex.c:579 __mutex_lock+0x840/0x9f4
DEBUG_LOCKS_WARN_ON(lock->magic != lock)
Modules linked in:
CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.18.0-rc1-00002-g3054695a0d27-dirty #55
Hardware name: Generic DT based system
 unwind_backtrace from show_stack+0x10/0x14
 show_stack from dump_stack_lvl+0x58/0x70
 dump_stack_lvl from __warn+0xc8/0x1e8
 __warn from warn_slowpath_fmt+0x78/0xa8
 warn_slowpath_fmt from __mutex_lock+0x840/0x9f4
 __mutex_lock from mutex_lock_nested+0x1c/0x24
 mutex_lock_nested from drm_bridge_hpd_enable+0x2c/0x84
 drm_bridge_hpd_enable from msm_hdmi_modeset_init+0xc0/0x21c
 msm_hdmi_modeset_init from mdp4_kms_init+0x53c/0x90c
 mdp4_kms_init from msm_drm_bind+0x514/0x698
 msm_drm_bind from try_to_bring_up_aggregate_device+0x160/0x1bc
 try_to_bring_up_aggregate_device from component_master_add_with_match+0xc4/0xf8
 component_master_add_with_match from msm_pdev_probe+0x274/0x350
 msm_pdev_probe from platform_probe+0x5c/0xbc
 platform_probe from really_probe.part.0+0x9c/0x290
 really_probe.part.0 from __driver_probe_device+0xa8/0x13c
 __driver_probe_device from driver_probe_device+0x34/0x10c
 driver_probe_device from __driver_attach+0xbc/0x178
 __driver_attach from bus_for_each_dev+0x74/0xc0
 bus_for_each_dev from bus_add_driver+0x160/0x1e4
 bus_add_driver from driver_register+0x88/0x118
 driver_register from do_one_initcall+0x6c/0x334
 do_one_initcall from kernel_init_freeable+0x1bc/0x220
 kernel_init_freeable from kernel_init+0x18/0x12c
 kernel_init from ret_from_fork+0x14/0x2c

Fixes: 3d3f8b1f8b62 ("drm/bridge: make bridge registration independent of drm flow")
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
---

I've added the Fixes tag pointing to the commit which added these
functions. Please correct me if you think it's wrong.

---
 drivers/gpu/drm/msm/dp/dp_drm.c        | 5 +++++
 drivers/gpu/drm/msm/dsi/dsi_manager.c  | 3 +++
 drivers/gpu/drm/msm/hdmi/hdmi_bridge.c | 3 +++
 drivers/gpu/drm/msm/msm_drv.c          | 3 +++
 4 files changed, 14 insertions(+)

diff --git a/drivers/gpu/drm/msm/dp/dp_drm.c b/drivers/gpu/drm/msm/dp/dp_drm.c
index 80f59cf99089..a7415f9eb80e 100644
--- a/drivers/gpu/drm/msm/dp/dp_drm.c
+++ b/drivers/gpu/drm/msm/dp/dp_drm.c
@@ -230,9 +230,13 @@ struct drm_bridge *msm_dp_bridge_init(struct msm_dp *dp_display, struct drm_devi
 	bridge->funcs = &dp_bridge_ops;
 	bridge->encoder = encoder;
 
+	drm_bridge_add(bridge);
+
 	rc = drm_bridge_attach(encoder, bridge, NULL, DRM_BRIDGE_ATTACH_NO_CONNECTOR);
 	if (rc) {
 		DRM_ERROR("failed to attach bridge, rc=%d\n", rc);
+		drm_bridge_remove(bridge);
+
 		return ERR_PTR(rc);
 	}
 
@@ -242,6 +246,7 @@ struct drm_bridge *msm_dp_bridge_init(struct msm_dp *dp_display, struct drm_devi
 					DRM_BRIDGE_ATTACH_NO_CONNECTOR);
 		if (rc < 0) {
 			DRM_ERROR("failed to attach panel bridge: %d\n", rc);
+			drm_bridge_detach(bridge);
 			drm_bridge_remove(bridge);
 			return ERR_PTR(rc);
 		}
diff --git a/drivers/gpu/drm/msm/dsi/dsi_manager.c b/drivers/gpu/drm/msm/dsi/dsi_manager.c
index 0c1b7dde377c..918498e71255 100644
--- a/drivers/gpu/drm/msm/dsi/dsi_manager.c
+++ b/drivers/gpu/drm/msm/dsi/dsi_manager.c
@@ -665,6 +665,8 @@ struct drm_bridge *msm_dsi_manager_bridge_init(u8 id)
 	bridge = &dsi_bridge->base;
 	bridge->funcs = &dsi_mgr_bridge_funcs;
 
+	drm_bridge_add(bridge);
+
 	ret = drm_bridge_attach(encoder, bridge, NULL, 0);
 	if (ret)
 		goto fail;
@@ -735,6 +737,7 @@ struct drm_connector *msm_dsi_manager_ext_bridge_init(u8 id)
 
 void msm_dsi_manager_bridge_destroy(struct drm_bridge *bridge)
 {
+	drm_bridge_remove(bridge);
 }
 
 int msm_dsi_manager_cmd_xfer(int id, const struct mipi_dsi_msg *msg)
diff --git a/drivers/gpu/drm/msm/hdmi/hdmi_bridge.c b/drivers/gpu/drm/msm/hdmi/hdmi_bridge.c
index 10ebe2089cb6..97c24010c4d1 100644
--- a/drivers/gpu/drm/msm/hdmi/hdmi_bridge.c
+++ b/drivers/gpu/drm/msm/hdmi/hdmi_bridge.c
@@ -15,6 +15,7 @@ void msm_hdmi_bridge_destroy(struct drm_bridge *bridge)
 	struct hdmi_bridge *hdmi_bridge = to_hdmi_bridge(bridge);
 
 	msm_hdmi_hpd_disable(hdmi_bridge);
+	drm_bridge_remove(bridge);
 }
 
 static void msm_hdmi_power_on(struct drm_bridge *bridge)
@@ -349,6 +350,8 @@ struct drm_bridge *msm_hdmi_bridge_init(struct hdmi *hdmi)
 		DRM_BRIDGE_OP_DETECT |
 		DRM_BRIDGE_OP_EDID;
 
+	drm_bridge_add(bridge);
+
 	ret = drm_bridge_attach(hdmi->encoder, bridge, NULL, DRM_BRIDGE_ATTACH_NO_CONNECTOR);
 	if (ret)
 		goto fail;
diff --git a/drivers/gpu/drm/msm/msm_drv.c b/drivers/gpu/drm/msm/msm_drv.c
index affa95eb05fc..71e1b7393f6f 100644
--- a/drivers/gpu/drm/msm/msm_drv.c
+++ b/drivers/gpu/drm/msm/msm_drv.c
@@ -232,6 +232,9 @@ static int msm_drm_uninit(struct device *dev)
 
 	drm_mode_config_cleanup(ddev);
 
+	for (i = 0; i < priv->num_bridges; i++)
+		drm_bridge_remove(priv->bridges[i]);
+
 	pm_runtime_get_sync(dev);
 	msm_irq_uninstall(ddev);
 	pm_runtime_put_sync(dev);
-- 
2.35.1

Re: [PATCH] drm/msm: properly add and remove internal bridges

[kernel test robot]

Hi Dmitry,

Thank you for the patch! Yet something to improve:

[auto build test ERROR on drm/drm-next]
[also build test ERROR on v5.18-rc2 next-20220411]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/intel-lab-lkp/linux/commits/Dmitry-Baryshkov/drm-msm-properly-add-and-remove-internal-bridges/20220408-210744
base:   git://anongit.freedesktop.org/drm/drm drm-next
config: arm64-defconfig (https://download.01.org/0day-ci/archive/20220411/202204112350.b4eldlK1-lkp@intel.com/config)
compiler: aarch64-linux-gcc (GCC) 11.2.0
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # https://github.com/intel-lab-lkp/linux/commit/fe14b6490aa99b01a424580fb84462519a9a310c
        git remote add linux-review https://github.com/intel-lab-lkp/linux
        git fetch --no-tags linux-review Dmitry-Baryshkov/drm-msm-properly-add-and-remove-internal-bridges/20220408-210744
        git checkout fe14b6490aa99b01a424580fb84462519a9a310c
        # save the config file to linux build tree
        mkdir build_dir
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.2.0 make.cross O=build_dir ARCH=arm64 SHELL=/bin/bash

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All errors (new ones prefixed by >>, old ones prefixed by <<):

>> ERROR: modpost: "drm_bridge_detach" [drivers/gpu/drm/msm/msm.ko] undefined!

-- 
0-DAY CI Kernel Test Service
https://01.org/lkp