From 820687befec471aff3bb59bd69302d34a776e807 Mon Sep 17 00:00:00 2001 From: Gustavo Padovan Date: Mon, 24 Nov 2014 16:37:26 +0900 Subject: drm/exynos: move Exynos platform drivers registration to init Registering the Exynos DRM subdevices platform drivers in the probe function is causing an infinite loop. Fix this by moving it to the exynos_drm_init() function to register the drivers on module init. Registering drivers in the probe functions causes a deadlock in the parent device lock. See Grant Likely explanation on the topic: "I think the problem is that exynos_drm_init() is registering a normal (non-OF) platform device, so the parent will be /sys/devices/platform. It immediately gets bound against exynos_drm_platform_driver which calls the exynos drm_platform_probe() hook. The driver core obtains device_lock() on the device *and on the device parent*. Inside the probe hook, additional platform_drivers get registered. Each time one does, it tries to bind against every platform device in the system, which includes the ones created by OF. When it attempts to bind, it obtains device_lock() on the device *and on the device parent*. Before the change to move of-generated platform devices into /sys/devices/platform, the devices had different parents. Now both devices have /sys/devices/platform as the parent, so yes they are going to deadlock. The real problem is registering drivers from within a probe hook. That is completely wrong for the above deadlock reason. __driver_attach() will deadlock. Those registrations must be pulled out of .probe(). Registering devices in .probe() is okay because __device_attach() doesn't try to obtain device_lock() on the parent." INFO: task swapper/0:1 blocked for more than 120 seconds. Not tainted 3.18.0-rc3-next-20141105 #794 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. swapper/0 D c052534c 0 1 0 0x00000000 [] (__schedule) from [] (schedule_preempt_disabled+0x14/0x20) [] (schedule_preempt_disabled) from [] (mutex_lock_nested+0x1c4/0x464 [] (mutex_lock_nested) from [] (__driver_attach+0x48/0x98) [] (__driver_attach) from [] (bus_for_each_dev+0x54/0x88) [] (bus_for_each_dev) from [] (bus_add_driver+0xe4/0x200) [] (bus_add_driver) from [] (driver_register+0x78/0xf4) [] (driver_register) from [] (exynos_drm_platform_probe+0x34/0x234) [] (exynos_drm_platform_probe) from [] (platform_drv_probe+0x48/0xa4) [] (platform_drv_probe) from [] (driver_probe_device+0x13c/0x37c) [] (driver_probe_device) from [] (__driver_attach+0x94/0x98) [] (__driver_attach) from [] (bus_for_each_dev+0x54/0x88) [] (bus_for_each_dev) from [] (bus_add_driver+0xe4/0x200) [] (bus_add_driver) from [] (driver_register+0x78/0xf4) [] (driver_register) from [] (exynos_drm_init+0x70/0xa0) [] (exynos_drm_init) from [] (do_one_initcall+0xac/0x1f0) [] (do_one_initcall) from [] (kernel_init_freeable+0x10c/0x1d8) [] (kernel_init_freeable) from [] (kernel_init+0x8/0xec) [] (kernel_init) from [] (ret_from_fork+0x14/0x2c) 3 locks held by swapper/0/1: #0: (&dev->mutex){......}, at: [] __driver_attach+0x48/0x98 #1: (&dev->mutex){......}, at: [] __driver_attach+0x58/0x98 #2: (&dev->mutex){......}, at: [] __driver_attach+0x48/0x98 Changelog v2: - call platform_driver_register after all kms and non kms drivers are registered - rebased it to exynos-drm-next Signed-off-by: Javier Martinez Canillas Signed-off-by: Gustavo Padovan Signed-off-by: Inki Dae --- drivers/gpu/drm/exynos/exynos_drm_drv.c | 105 +++++++++++++++----------------- 1 file changed, 48 insertions(+), 57 deletions(-) diff --git a/drivers/gpu/drm/exynos/exynos_drm_drv.c b/drivers/gpu/drm/exynos/exynos_drm_drv.c index 2ca0c5dcf80e..c5cb8b6c85a9 100644 --- a/drivers/gpu/drm/exynos/exynos_drm_drv.c +++ b/drivers/gpu/drm/exynos/exynos_drm_drv.c @@ -591,73 +591,22 @@ static struct platform_driver *const exynos_drm_non_kms_drivers[] = { static int exynos_drm_platform_probe(struct platform_device *pdev) { struct component_match *match; - int ret, i, j; pdev->dev.coherent_dma_mask = DMA_BIT_MASK(32); exynos_drm_driver.num_ioctls = ARRAY_SIZE(exynos_ioctls); - for (i = 0; i < ARRAY_SIZE(exynos_drm_kms_drivers); ++i) { - ret = platform_driver_register(exynos_drm_kms_drivers[i]); - if (ret < 0) - goto err_unregister_kms_drivers; - } - match = exynos_drm_match_add(&pdev->dev); if (IS_ERR(match)) { - ret = PTR_ERR(match); - goto err_unregister_kms_drivers; + return PTR_ERR(match); } - ret = component_master_add_with_match(&pdev->dev, &exynos_drm_ops, - match); - if (ret < 0) - goto err_unregister_kms_drivers; - - for (j = 0; j < ARRAY_SIZE(exynos_drm_non_kms_drivers); ++j) { - ret = platform_driver_register(exynos_drm_non_kms_drivers[j]); - if (ret < 0) - goto err_del_component_master; - } - - ret = exynos_platform_device_ipp_register(); - if (ret < 0) - goto err_unregister_non_kms_drivers; - - return ret; - -#ifdef CONFIG_DRM_EXYNOS_IPP - exynos_platform_device_ipp_unregister(); -#endif -err_unregister_non_kms_drivers: - while (--j >= 0) - platform_driver_unregister(exynos_drm_non_kms_drivers[j]); - -err_del_component_master: - component_master_del(&pdev->dev, &exynos_drm_ops); - -err_unregister_kms_drivers: - while (--i >= 0) - platform_driver_unregister(exynos_drm_kms_drivers[i]); - - return ret; + return component_master_add_with_match(&pdev->dev, &exynos_drm_ops, + match); } static int exynos_drm_platform_remove(struct platform_device *pdev) { - int i; - -#ifdef CONFIG_DRM_EXYNOS_IPP - exynos_platform_device_ipp_unregister(); -#endif - - for (i = ARRAY_SIZE(exynos_drm_non_kms_drivers) - 1; i >= 0; --i) - platform_driver_unregister(exynos_drm_non_kms_drivers[i]); - component_master_del(&pdev->dev, &exynos_drm_ops); - - for (i = ARRAY_SIZE(exynos_drm_kms_drivers) - 1; i >= 0; --i) - platform_driver_unregister(exynos_drm_kms_drivers[i]); - return 0; } @@ -673,7 +622,7 @@ static struct platform_driver exynos_drm_platform_driver = { static int exynos_drm_init(void) { - int ret; + int ret, i, j; /* * Register device object only in case of Exynos SoC. @@ -696,13 +645,43 @@ static int exynos_drm_init(void) if (ret < 0) goto err_unregister_pd; + for (i = 0; i < ARRAY_SIZE(exynos_drm_kms_drivers); ++i) { + ret = platform_driver_register(exynos_drm_kms_drivers[i]); + if (ret < 0) + goto err_unregister_kms_drivers; + } + + for (j = 0; j < ARRAY_SIZE(exynos_drm_non_kms_drivers); ++j) { + ret = platform_driver_register(exynos_drm_non_kms_drivers[j]); + if (ret < 0) + goto err_unregister_non_kms_drivers; + } + +#ifdef CONFIG_DRM_EXYNOS_IPP + ret = exynos_platform_device_ipp_register(); + if (ret < 0) + goto err_unregister_non_kms_drivers; +#endif + ret = platform_driver_register(&exynos_drm_platform_driver); if (ret) - goto err_remove_vidi; + goto err_unregister_resources; return 0; -err_remove_vidi: +err_unregister_resources: +#ifdef CONFIG_DRM_EXYNOS_IPP + exynos_platform_device_ipp_unregister(); +#endif + +err_unregister_non_kms_drivers: + while (--j >= 0) + platform_driver_unregister(exynos_drm_non_kms_drivers[j]); + +err_unregister_kms_drivers: + while (--i >= 0) + platform_driver_unregister(exynos_drm_kms_drivers[i]); + exynos_drm_remove_vidi(); err_unregister_pd: @@ -713,6 +692,18 @@ err_unregister_pd: static void exynos_drm_exit(void) { + int i; + +#ifdef CONFIG_DRM_EXYNOS_IPP + exynos_platform_device_ipp_unregister(); +#endif + + for (i = ARRAY_SIZE(exynos_drm_non_kms_drivers) - 1; i >= 0; --i) + platform_driver_unregister(exynos_drm_non_kms_drivers[i]); + + for (i = ARRAY_SIZE(exynos_drm_kms_drivers) - 1; i >= 0; --i) + platform_driver_unregister(exynos_drm_kms_drivers[i]); + platform_driver_unregister(&exynos_drm_platform_driver); exynos_drm_remove_vidi(); -- cgit v1.2.2