Merge tag 'driver-core-5.7-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core

Pull driver core updates from Greg KH:
 "Here is the "big" set of driver core changes for 5.7-rc1.

  Nothing huge in here, just lots of little firmware core changes and
  use of new apis, a libfs fix, a debugfs api change, and some driver
  core deferred probe rework.

  All of these have been in linux-next for a while with no reported
  issues"

* tag 'driver-core-5.7-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (44 commits)
  Revert "driver core: Set fw_devlink to "permissive" behavior by default"
  driver core: Set fw_devlink to "permissive" behavior by default
  driver core: Replace open-coded list_last_entry()
  driver core: Read atomic counter once in driver_probe_done()
  libfs: fix infoleak in simple_attr_read()
  driver core: Add device links from fwnode only for the primary device
  platform/x86: touchscreen_dmi: Add info for the Chuwi Vi8 Plus tablet
  platform/x86: touchscreen_dmi: Add EFI embedded firmware info support
  Input: icn8505 - Switch to firmware_request_platform for retreiving the fw
  Input: silead - Switch to firmware_request_platform for retreiving the fw
  selftests: firmware: Add firmware_request_platform tests
  test_firmware: add support for firmware_request_platform
  firmware: Add new platform fallback mechanism and firmware_request_platform()
  Revert "drivers: base: power: wakeup.c: Use built-in RCU list checking"
  drivers: base: power: wakeup.c: Use built-in RCU list checking
  component: allow missing unbind callback
  debugfs: remove return value of debugfs_create_file_size()
  debugfs: Check module state before warning in {full/open}_proxy_open()
  firmware: fix a double abort case with fw_load_sysfs_fallback
  arch_topology: Fix putting invalid cpu clk
  ...

48 files changed, 996 insertions, 174 deletions

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index d7da466fd5c3..6a0822c98e1d 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -1360,6 +1360,24 @@
 			can be changed at run time by the max_graph_depth file
 			in the tracefs tracing directory. default: 0 (no limit)
 
+	fw_devlink=	[KNL] Create device links between consumer and supplier
+			devices by scanning the firmware to infer the
+			consumer/supplier relationships. This feature is
+			especially useful when drivers are loaded as modules as
+			it ensures proper ordering of tasks like device probing
+			(suppliers first, then consumers), supplier boot state
+			clean up (only after all consumers have probed),
+			suspend/resume & runtime PM (consumers first, then
+			suppliers).
+			Format: { off | permissive | on | rpm }
+			off --	Don't create device links from firmware info.
+			permissive -- Create device links from firmware info
+				but use it only for ordering boot state clean
+				up (sync_state() calls).
+			on -- 	Create device links from firmware info and use it
+				to enforce probe and suspend/resume ordering.
+			rpm --	Like "on", but also use to order runtime PM.
+
 	gamecon.map[2|3]=
 			[HW,JOY] Multisystem joystick and NES/SNES/PSX pad
 			support via parallel port (up to 5 devices per port)
@@ -3291,12 +3309,6 @@
 			This can be set from sysctl after boot.
 			See Documentation/admin-guide/sysctl/vm.rst for details.
 
-	of_devlink	[OF, KNL] Create device links between consumer and
-			supplier devices by scanning the devictree to infer the
-			consumer/supplier relationships.  A consumer device
-			will not be probed until all the supplier devices have
-			probed successfully.
-
 	ohci1394_dma=early	[HW] enable debugging via the ohci1394 driver.
 			See Documentation/debugging-via-ohci1394.txt for more
 			info.
diff --git a/Documentation/driver-api/firmware/fallback-mechanisms.rst b/Documentation/driver-api/firmware/fallback-mechanisms.rst
index 8b041d0ab426..036383dad6d6 100644
--- a/Documentation/driver-api/firmware/fallback-mechanisms.rst
+++ b/Documentation/driver-api/firmware/fallback-mechanisms.rst
@@ -202,3 +202,106 @@ the following file:
 
 If you echo 0 into it means MAX_JIFFY_OFFSET will be used. The data type
 for the timeout is an int.
+
+EFI embedded firmware fallback mechanism
+========================================
+
+On some devices the system's EFI code / ROM may contain an embedded copy
+of firmware for some of the system's integrated peripheral devices and
+the peripheral's Linux device-driver needs to access this firmware.
+
+Device drivers which need such firmware can use the
+firmware_request_platform() function for this, note that this is a
+separate fallback mechanism from the other fallback mechanisms and
+this does not use the sysfs interface.
+
+A device driver which needs this can describe the firmware it needs
+using an efi_embedded_fw_desc struct:
+
+.. kernel-doc:: include/linux/efi_embedded_fw.h
+   :functions: efi_embedded_fw_desc
+
+The EFI embedded-fw code works by scanning all EFI_BOOT_SERVICES_CODE memory
+segments for an eight byte sequence matching prefix; if the prefix is found it
+then does a sha256 over length bytes and if that matches makes a copy of length
+bytes and adds that to its list with found firmwares.
+
+To avoid doing this somewhat expensive scan on all systems, dmi matching is
+used. Drivers are expected to export a dmi_system_id array, with each entries'
+driver_data pointing to an efi_embedded_fw_desc.
+
+To register this array with the efi-embedded-fw code, a driver needs to:
+
+1. Always be builtin to the kernel or store the dmi_system_id array in a
+   separate object file which always gets builtin.
+
+2. Add an extern declaration for the dmi_system_id array to
+   include/linux/efi_embedded_fw.h.
+
+3. Add the dmi_system_id array to the embedded_fw_table in
+   drivers/firmware/efi/embedded-firmware.c wrapped in a #ifdef testing that
+   the driver is being builtin.
+
+4. Add "select EFI_EMBEDDED_FIRMWARE if EFI_STUB" to its Kconfig entry.
+
+The firmware_request_platform() function will always first try to load firmware
+with the specified name directly from the disk, so the EFI embedded-fw can
+always be overridden by placing a file under /lib/firmware.
+
+Note that:
+
+1. The code scanning for EFI embedded-firmware runs near the end
+   of start_kernel(), just before calling rest_init(). For normal drivers and
+   subsystems using subsys_initcall() to register themselves this does not
+   matter. This means that code running earlier cannot use EFI
+   embedded-firmware.
+
+2. At the moment the EFI embedded-fw code assumes that firmwares always start at
+   an offset which is a multiple of 8 bytes, if this is not true for your case
+   send in a patch to fix this.
+
+3. At the moment the EFI embedded-fw code only works on x86 because other archs
+   free EFI_BOOT_SERVICES_CODE before the EFI embedded-fw code gets a chance to
+   scan it.
+
+4. The current brute-force scanning of EFI_BOOT_SERVICES_CODE is an ad-hoc
+   brute-force solution. There has been discussion to use the UEFI Platform
+   Initialization (PI) spec's Firmware Volume protocol. This has been rejected
+   because the FV Protocol relies on *internal* interfaces of the PI spec, and:
+   1. The PI spec does not define peripheral firmware at all
+   2. The internal interfaces of the PI spec do not guarantee any backward
+   compatibility. Any implementation details in FV may be subject to change,
+   and may vary system to system. Supporting the FV Protocol would be
+   difficult as it is purposely ambiguous.
+
+Example how to check for and extract embedded firmware
+------------------------------------------------------
+
+To check for, for example Silead touchscreen controller embedded firmware,
+do the following:
+
+1. Boot the system with efi=debug on the kernel commandline
+
+2. cp /sys/kernel/debug/efi/boot_services_code? to your home dir
+
+3. Open the boot_services_code? files in a hex-editor, search for the
+   magic prefix for Silead firmware: F0 00 00 00 02 00 00 00, this gives you
+   the beginning address of the firmware inside the boot_services_code? file.
+
+4. The firmware has a specific pattern, it starts with a 8 byte page-address,
+   typically F0 00 00 00 02 00 00 00 for the first page followed by 32-bit
+   word-address + 32-bit value pairs. With the word-address incrementing 4
+   bytes (1 word) for each pair until a page is complete. A complete page is
+   followed by a new page-address, followed by more word + value pairs. This
+   leads to a very distinct pattern. Scroll down until this pattern stops,
+   this gives you the end of the firmware inside the boot_services_code? file.
+
+5. "dd if=boot_services_code? of=firmware bs=1 skip=<begin-addr> count=<len>"
+   will extract the firmware for you. Inspect the firmware file in a
+   hexeditor to make sure you got the dd parameters correct.
+
+6. Copy it to /lib/firmware under the expected name to test it.
+
+7. If the extracted firmware works, you can use the found info to fill an
+   efi_embedded_fw_desc struct to describe it, run "sha256sum firmware"
+   to get the sha256sum to put in the sha256 field.
diff --git a/Documentation/driver-api/firmware/lookup-order.rst b/Documentation/driver-api/firmware/lookup-order.rst
index 88c81739683c..6064672a782e 100644
--- a/Documentation/driver-api/firmware/lookup-order.rst
+++ b/Documentation/driver-api/firmware/lookup-order.rst
@@ -12,6 +12,8 @@ a driver issues a firmware API call.
   return it immediately
 * The ''Direct filesystem lookup'' is performed next, if found we
   return it immediately
+* The ''Platform firmware fallback'' is performed next, but only when
+  firmware_request_platform() is used, if found we return it immediately
 * If no firmware has been found and the fallback mechanism was enabled
   the sysfs interface is created. After this either a kobject uevent
   is issued or the custom firmware loading is relied upon for firmware
diff --git a/Documentation/driver-api/firmware/request_firmware.rst b/Documentation/driver-api/firmware/request_firmware.rst
index f62bdcbfed5b..cd076462d235 100644
--- a/Documentation/driver-api/firmware/request_firmware.rst
+++ b/Documentation/driver-api/firmware/request_firmware.rst
@@ -25,6 +25,11 @@ firmware_request_nowarn
 .. kernel-doc:: drivers/base/firmware_loader/main.c
    :functions: firmware_request_nowarn
 
+firmware_request_platform
+-------------------------
+.. kernel-doc:: drivers/base/firmware_loader/main.c
+   :functions: firmware_request_platform
+
 request_firmware_direct
 -----------------------
 .. kernel-doc:: drivers/base/firmware_loader/main.c
diff --git a/Documentation/filesystems/debugfs.rst b/Documentation/filesystems/debugfs.rst
index 80f332b8eb68..db9ea0854040 100644
--- a/Documentation/filesystems/debugfs.rst
+++ b/Documentation/filesystems/debugfs.rst
@@ -62,10 +62,10 @@ missing.
 Create a file with an initial size, the following function can be used
 instead::
 
-    struct dentry *debugfs_create_file_size(const char *name, umode_t mode,
-				struct dentry *parent, void *data,
-				const struct file_operations *fops,
-				loff_t file_size);
+    void debugfs_create_file_size(const char *name, umode_t mode,
+				  struct dentry *parent, void *data,
+				  const struct file_operations *fops,
+				  loff_t file_size);
 
 file_size is the initial file size. The other parameters are the same
 as the function debugfs_create_file.
diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c
index ae923ee8e2b4..a4ea04603af3 100644
--- a/arch/x86/platform/efi/efi.c
+++ b/arch/x86/platform/efi/efi.c
@@ -243,6 +243,7 @@ int __init efi_memblock_x86_reserve_range(void)
 	     efi.memmap.desc_version);
 
 	memblock_reserve(pmap, efi.memmap.nr_map * efi.memmap.desc_size);
+	set_bit(EFI_PRESERVE_BS_REGIONS, &efi.flags);
 
 	return 0;
 }
@@ -943,6 +944,7 @@ static void __init __efi_enter_virtual_mode(void)
 		goto err;
 	}
 
+	efi_check_for_embedded_firmwares();
 	efi_free_boot_services();
 
 	/*
diff --git a/arch/x86/platform/efi/quirks.c b/arch/x86/platform/efi/quirks.c
index 88d32c06cffa..bada1037b711 100644
--- a/arch/x86/platform/efi/quirks.c
+++ b/arch/x86/platform/efi/quirks.c
@@ -410,6 +410,10 @@ void __init efi_free_boot_services(void)
 	int num_entries = 0;
 	void *new, *new_md;
 
+	/* Keep all regions for /sys/kernel/debug/efi */
+	if (efi_enabled(EFI_DBG))
+		return;
+
 	for_each_efi_memory_desc(md) {
 		unsigned long long start = md->phys_addr;
 		unsigned long long size = md->num_pages << EFI_PAGE_SHIFT;
diff --git a/drivers/base/arch_topology.c b/drivers/base/arch_topology.c
index 6119e11a9f95..e5d691cf824c 100644
--- a/drivers/base/arch_topology.c
+++ b/drivers/base/arch_topology.c
@@ -94,7 +94,7 @@ static void update_topology_flags_workfn(struct work_struct *work)
 	update_topology = 0;
 }
 
-static u32 capacity_scale;
+static DEFINE_PER_CPU(u32, freq_factor) = 1;
 static u32 *raw_capacity;
 
 static int free_raw_capacity(void)
@@ -108,17 +108,23 @@ static int free_raw_capacity(void)
 void topology_normalize_cpu_scale(void)
 {
 	u64 capacity;
+	u64 capacity_scale;
 	int cpu;
 
 	if (!raw_capacity)
 		return;
 
-	pr_debug("cpu_capacity: capacity_scale=%u\n", capacity_scale);
+	capacity_scale = 1;
 	for_each_possible_cpu(cpu) {
-		pr_debug("cpu_capacity: cpu=%d raw_capacity=%u\n",
-			 cpu, raw_capacity[cpu]);
-		capacity = (raw_capacity[cpu] << SCHED_CAPACITY_SHIFT)
-			/ capacity_scale;
+		capacity = raw_capacity[cpu] * per_cpu(freq_factor, cpu);
+		capacity_scale = max(capacity, capacity_scale);
+	}
+
+	pr_debug("cpu_capacity: capacity_scale=%llu\n", capacity_scale);
+	for_each_possible_cpu(cpu) {
+		capacity = raw_capacity[cpu] * per_cpu(freq_factor, cpu);
+		capacity = div64_u64(capacity << SCHED_CAPACITY_SHIFT,
+			capacity_scale);
 		topology_set_cpu_scale(cpu, capacity);
 		pr_debug("cpu_capacity: CPU%d cpu_capacity=%lu\n",
 			cpu, topology_get_cpu_scale(cpu));
@@ -127,6 +133,7 @@ void topology_normalize_cpu_scale(void)
 
 bool __init topology_parse_cpu_capacity(struct device_node *cpu_node, int cpu)
 {
+	struct clk *cpu_clk;
 	static bool cap_parsing_failed;
 	int ret;
 	u32 cpu_capacity;
@@ -146,10 +153,22 @@ bool __init topology_parse_cpu_capacity(struct device_node *cpu_node, int cpu)
 				return false;
 			}
 		}
-		capacity_scale = max(cpu_capacity, capacity_scale);
 		raw_capacity[cpu] = cpu_capacity;
 		pr_debug("cpu_capacity: %pOF cpu_capacity=%u (raw)\n",
 			cpu_node, raw_capacity[cpu]);
+
+		/*
+		 * Update freq_factor for calculating early boot cpu capacities.
+		 * For non-clk CPU DVFS mechanism, there's no way to get the
+		 * frequency value now, assuming they are running at the same
+		 * frequency (by keeping the initial freq_factor value).
+		 */
+		cpu_clk = of_clk_get(cpu_node, 0);
+		if (!PTR_ERR_OR_ZERO(cpu_clk)) {
+			per_cpu(freq_factor, cpu) =
+				clk_get_rate(cpu_clk) / 1000;
+			clk_put(cpu_clk);
+		}
 	} else {
 		if (raw_capacity) {
 			pr_err("cpu_capacity: missing %pOF raw capacity\n",
@@ -188,11 +207,8 @@ init_cpu_capacity_callback(struct notifier_block *nb,
 
 	cpumask_andnot(cpus_to_visit, cpus_to_visit, policy->related_cpus);
 
-	for_each_cpu(cpu, policy->related_cpus) {
-		raw_capacity[cpu] = topology_get_cpu_scale(cpu) *
-				    policy->cpuinfo.max_freq / 1000UL;
-		capacity_scale = max(raw_capacity[cpu], capacity_scale);
-	}
+	for_each_cpu(cpu, policy->related_cpus)
+		per_cpu(freq_factor, cpu) = policy->cpuinfo.max_freq / 1000;
 
 	if (cpumask_empty(cpus_to_visit)) {
 		topology_normalize_cpu_scale();
@@ -281,7 +297,7 @@ static int __init get_cpu_for_node(struct device_node *node)
 static int __init parse_core(struct device_node *core, int package_id,
 			     int core_id)
 {
-	char name[10];
+	char name[20];
 	bool leaf = true;
 	int i = 0;
 	int cpu;
@@ -327,7 +343,7 @@ static int __init parse_core(struct device_node *core, int package_id,
 
 static int __init parse_cluster(struct device_node *cluster, int depth)
 {
-	char name[10];
+	char name[20];
 	bool leaf = true;
 	bool has_cores = false;
 	struct device_node *c;
diff --git a/drivers/base/component.c b/drivers/base/component.c
index c7879f5ae2fb..e97704104784 100644
--- a/drivers/base/component.c
+++ b/drivers/base/component.c
@@ -528,7 +528,8 @@ static void component_unbind(struct component *component,
 {
 	WARN_ON(!component->bound);
 
-	component->ops->unbind(component->dev, master->dev, data);
+	if (component->ops && component->ops->unbind)
+		component->ops->unbind(component->dev, master->dev, data);
 	component->bound = false;
 
 	/* Release all resources claimed in the binding of this component */
diff --git a/drivers/base/core.c b/drivers/base/core.c
index dbb0f9130f42..5e3cc1651c78 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -64,12 +64,12 @@ static inline void device_links_write_unlock(void)
 	mutex_unlock(&device_links_lock);
 }
 
-int device_links_read_lock(void)
+int device_links_read_lock(void) __acquires(&device_links_srcu)
 {
 	return srcu_read_lock(&device_links_srcu);
 }
 
-void device_links_read_unlock(int idx)
+void device_links_read_unlock(int idx) __releases(&device_links_srcu)
 {
 	srcu_read_unlock(&device_links_srcu, idx);
 }
@@ -523,9 +523,13 @@ static void device_link_add_missing_supplier_links(void)
 
 	mutex_lock(&wfs_lock);
 	list_for_each_entry_safe(dev, tmp, &wait_for_suppliers,
-				 links.needs_suppliers)
-		if (!fwnode_call_int_op(dev->fwnode, add_links, dev))
+				 links.needs_suppliers) {
+		int ret = fwnode_call_int_op(dev->fwnode, add_links, dev);
+		if (!ret)
 			list_del_init(&dev->links.needs_suppliers);
+		else if (ret != -ENODEV)
+			dev->links.need_for_probe = false;
+	}
 	mutex_unlock(&wfs_lock);
 }
 
@@ -2341,6 +2345,31 @@ static int device_private_init(struct device *dev)
 	return 0;
 }
 
+static u32 fw_devlink_flags;
+static int __init fw_devlink_setup(char *arg)
+{
+	if (!arg)
+		return -EINVAL;
+
+	if (strcmp(arg, "off") == 0) {
+		fw_devlink_flags = 0;
+	} else if (strcmp(arg, "permissive") == 0) {
+		fw_devlink_flags = DL_FLAG_SYNC_STATE_ONLY;
+	} else if (strcmp(arg, "on") == 0) {
+		fw_devlink_flags = DL_FLAG_AUTOPROBE_CONSUMER;
+	} else if (strcmp(arg, "rpm") == 0) {
+		fw_devlink_flags = DL_FLAG_AUTOPROBE_CONSUMER |
+				   DL_FLAG_PM_RUNTIME;
+	}
+	return 0;
+}
+early_param("fw_devlink", fw_devlink_setup);
+
+u32 fw_devlink_get_flags(void)
+{
+	return fw_devlink_flags;
+}
+
 /**
  * device_add - add device to device hierarchy.
  * @dev: device.
@@ -2375,6 +2404,7 @@ int device_add(struct device *dev)
 	struct class_interface *class_intf;
 	int error = -EINVAL, fw_ret;
 	struct kobject *glue_dir = NULL;
+	bool is_fwnode_dev = false;
 
 	dev = get_device(dev);
 	if (!dev)
@@ -2472,8 +2502,10 @@ int device_add(struct device *dev)
 
 	kobject_uevent(&dev->kobj, KOBJ_ADD);
 
-	if (dev->fwnode && !dev->fwnode->dev)
+	if (dev->fwnode && !dev->fwnode->dev) {
 		dev->fwnode->dev = dev;
+		is_fwnode_dev = true;
+	}
 
 	/*
 	 * Check if any of the other devices (consumers) have been waiting for
@@ -2489,7 +2521,8 @@ int device_add(struct device *dev)
 	 */
 	device_link_add_missing_supplier_links();
 
-	if (fwnode_has_op(dev->fwnode, add_links)) {
+	if (fw_devlink_flags && is_fwnode_dev &&
+	    fwnode_has_op(dev->fwnode, add_links)) {
 		fw_ret = fwnode_call_int_op(dev->fwnode, add_links, dev);
 		if (fw_ret == -ENODEV)
 			device_link_wait_for_mandatory_supplier(dev);
diff --git a/drivers/base/cpu.c b/drivers/base/cpu.c
index 6265871a4af2..df19c002d747 100644
--- a/drivers/base/cpu.c
+++ b/drivers/base/cpu.c
@@ -231,8 +231,7 @@ static struct cpu_attr cpu_attrs[] = {
 static ssize_t print_cpus_kernel_max(struct device *dev,
 				     struct device_attribute *attr, char *buf)
 {
-	int n = snprintf(buf, PAGE_SIZE-2, "%d\n", NR_CPUS - 1);
-	return n;
+	return sprintf(buf, "%d\n", NR_CPUS - 1);
 }
 static DEVICE_ATTR(kernel_max, 0444, print_cpus_kernel_max, NULL);
 
@@ -258,13 +257,13 @@ static ssize_t print_cpus_offline(struct device *dev,
 			buf[n++] = ',';
 
 		if (nr_cpu_ids == total_cpus-1)
-			n += snprintf(&buf[n], len - n, "%u", nr_cpu_ids);
+			n += scnprintf(&buf[n], len - n, "%u", nr_cpu_ids);
 		else
-			n += snprintf(&buf[n], len - n, "%u-%d",
+			n += scnprintf(&buf[n], len - n, "%u-%d",
 						      nr_cpu_ids, total_cpus-1);
 	}
 
-	n += snprintf(&buf[n], len - n, "\n");
+	n += scnprintf(&buf[n], len - n, "\n");
 	return n;
 }
 static DEVICE_ATTR(offline, 0444, print_cpus_offline, NULL);
@@ -272,7 +271,7 @@ static DEVICE_ATTR(offline, 0444, print_cpus_offline, NULL);
 static ssize_t print_cpus_isolated(struct device *dev,
 				  struct device_attribute *attr, char *buf)
 {
-	int n = 0, len = PAGE_SIZE-2;
+	int n;
 	cpumask_var_t isolated;
 
 	if (!alloc_cpumask_var(&isolated, GFP_KERNEL))
@@ -280,7 +279,7 @@ static ssize_t print_cpus_isolated(struct device *dev,
 
 	cpumask_andnot(isolated, cpu_possible_mask,
 		       housekeeping_cpumask(HK_FLAG_DOMAIN));
-	n = scnprintf(buf, len, "%*pbl\n", cpumask_pr_args(isolated));
+	n = sprintf(buf, "%*pbl\n", cpumask_pr_args(isolated));
 
 	free_cpumask_var(isolated);
 
@@ -292,11 +291,7 @@ static DEVICE_ATTR(isolated, 0444, print_cpus_isolated, NULL);
 static ssize_t print_cpus_nohz_full(struct device *dev,
 				  struct device_attribute *attr, char *buf)
 {
-	int n = 0, len = PAGE_SIZE-2;
-
-	n = scnprintf(buf, len, "%*pbl\n", cpumask_pr_args(tick_nohz_full_mask));
-
-	return n;
+	return sprintf(buf, "%*pbl\n", cpumask_pr_args(tick_nohz_full_mask));
 }
 static DEVICE_ATTR(nohz_full, 0444, print_cpus_nohz_full, NULL);
 #endif
diff --git a/drivers/base/dd.c b/drivers/base/dd.c
index b25bcab2a26b..06ec0e851fa1 100644
--- a/drivers/base/dd.c
+++ b/drivers/base/dd.c
@@ -224,76 +224,52 @@ static int deferred_devs_show(struct seq_file *s, void *data)
 }
 DEFINE_SHOW_ATTRIBUTE(deferred_devs);
 
-static int deferred_probe_timeout = -1;
+#ifdef CONFIG_MODULES
+/*
+ * In the case of modules, set the default probe timeout to
+ * 30 seconds to give userland some time to load needed modules
+ */
+int driver_deferred_probe_timeout = 30;
+#else
+/* In the case of !modules, no probe timeout needed */
+int driver_deferred_probe_timeout = -1;
+#endif
+EXPORT_SYMBOL_GPL(driver_deferred_probe_timeout);
+
 static int __init deferred_probe_timeout_setup(char *str)
 {
 	int timeout;
 
 	if (!kstrtoint(str, 10, &timeout))
-		deferred_probe_timeout = timeout;
+		driver_deferred_probe_timeout = timeout;
 	return 1;
 }
 __setup("deferred_probe_timeout=", deferred_probe_timeout_setup);
 
-static int __driver_deferred_probe_check_state(struct device *dev)
-{
-	if (!initcalls_done)
-		return -EPROBE_DEFER;
-
-	if (!deferred_probe_timeout) {
-		dev_WARN(dev, "deferred probe timeout, ignoring dependency");
-		return -ETIMEDOUT;
-	}
-
-	return 0;
-}
-
 /**
  * driver_deferred_probe_check_state() - Check deferred probe state
  * @dev: device to check
  *
- * Returns -ENODEV if init is done and all built-in drivers have had a chance
- * to probe (i.e. initcalls are done), -ETIMEDOUT if deferred probe debug
- * timeout has expired, or -EPROBE_DEFER if none of those conditions are met.
+ * Return:
+ * -ENODEV if initcalls have completed and modules are disabled.
+ * -ETIMEDOUT if the deferred probe timeout was set and has expired
+ *  and modules are enabled.
+ * -EPROBE_DEFER in other cases.
  *
  * Drivers or subsystems can opt-in to calling this function instead of directly
  * returning -EPROBE_DEFER.
  */
 int driver_deferred_probe_check_state(struct device *dev)
 {
-	int ret;
-
-	ret = __driver_deferred_probe_check_state(dev);
-	if (ret < 0)
-		return ret;
-
-	dev_warn(dev, "ignoring dependency for device, assuming no driver");
-
-	return -ENODEV;
-}
-
-/**
- * driver_deferred_probe_check_state_continue() - check deferred probe state
- * @dev: device to check
- *
- * Returns -ETIMEDOUT if deferred probe debug timeout has expired, or
- * -EPROBE_DEFER otherwise.
- *
- * Drivers or subsystems can opt-in to calling this function instead of
- * directly returning -EPROBE_DEFER.
- *
- * This is similar to driver_deferred_probe_check_state(), but it allows the
- * subsystem to keep deferring probe after built-in drivers have had a chance
- * to probe. One scenario where that is