diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 256b1e5c63dd..2ff08a3d3e46 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -897,6 +897,10 @@ The filter can be disabled or changed to another driver later using sysfs. + driver_async_probe= [KNL] + List of driver names to be probed asynchronously. + Format: ,... + drm.edid_firmware=[:][,[:]] Broken monitors, graphic adapters, KVMs and EDIDless panels may send no or incorrect EDID data sets. diff --git a/drivers/base/dd.c b/drivers/base/dd.c index 5f6416e6ba96..ef3d5c9a7abe 100644 --- a/drivers/base/dd.c +++ b/drivers/base/dd.c @@ -57,6 +57,10 @@ static atomic_t deferred_trigger_count = ATOMIC_INIT(0); static struct dentry *deferred_devices; static bool initcalls_done; +/* Save the async probe drivers' name from kernel cmdline */ +#define ASYNC_DRV_NAMES_MAX_LEN 256 +static char async_probe_drv_names[ASYNC_DRV_NAMES_MAX_LEN]; + /* * In some cases, like suspend to RAM or hibernation, It might be reasonable * to prohibit probing of devices as it could be unsafe. @@ -671,6 +675,23 @@ int driver_probe_device(struct device_driver *drv, struct device *dev) return ret; } +static inline bool cmdline_requested_async_probing(const char *drv_name) +{ + return parse_option_str(async_probe_drv_names, drv_name); +} + +/* The option format is "driver_async_probe=drv_name1,drv_name2,..." */ +static int __init save_async_options(char *buf) +{ + if (strlen(buf) >= ASYNC_DRV_NAMES_MAX_LEN) + printk(KERN_WARNING + "Too long list of driver names for 'driver_async_probe'!\n"); + + strlcpy(async_probe_drv_names, buf, ASYNC_DRV_NAMES_MAX_LEN); + return 0; +} +__setup("driver_async_probe=", save_async_options); + bool driver_allows_async_probing(struct device_driver *drv) { switch (drv->probe_type) { @@ -681,6 +702,9 @@ bool driver_allows_async_probing(struct device_driver *drv) return false; default: + if (cmdline_requested_async_probing(drv->name)) + return true; + if (module_requested_async_probing(drv->owner)) return true;