diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index 255ec535bba803699f4608fc99b05810582b5c14..54983246930d1aeb922c3691ac0b5a96028d97ef 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -1370,6 +1370,9 @@ running once the system is up. Reserves a hole at the top of the kernel virtual address space. + reset_devices [KNL] Force drivers to reset the underlying device + during initialization. + resume= [SWSUSP] Specify the partition device for software suspend diff --git a/include/linux/init.h b/include/linux/init.h index 6667785dd1ff22d7452b716b380e7475158ee8b9..e92b1455d7afd8c908bfc0722be018a09c46c226 100644 --- a/include/linux/init.h +++ b/include/linux/init.h @@ -68,6 +68,7 @@ extern initcall_t __security_initcall_start[], __security_initcall_end[]; /* Defined in init/main.c */ extern char saved_command_line[]; +extern unsigned int reset_devices; /* used by init/main.c */ extern void setup_arch(char **); diff --git a/init/main.c b/init/main.c index 913e48d658ee1de1938edf62dfee2d497b02448f..0766e69712b2a86efa74caf3c5bd487bbbcd3753 100644 --- a/init/main.c +++ b/init/main.c @@ -127,6 +127,18 @@ static char *ramdisk_execute_command; /* Setup configured maximum number of CPUs to activate */ static unsigned int max_cpus = NR_CPUS; +/* + * If set, this is an indication to the drivers that reset the underlying + * device before going ahead with the initialization otherwise driver might + * rely on the BIOS and skip the reset operation. + * + * This is useful if kernel is booting in an unreliable environment. + * For ex. kdump situaiton where previous kernel has crashed, BIOS has been + * skipped and devices will be in unknown state. + */ +unsigned int reset_devices; +EXPORT_SYMBOL(reset_devices); + /* * Setup routine for controlling SMP activation * @@ -153,6 +165,14 @@ static int __init maxcpus(char *str) __setup("maxcpus=", maxcpus); +static int __init set_reset_devices(char *str) +{ + reset_devices = 1; + return 1; +} + +__setup("reset_devices", set_reset_devices); + static char * argv_init[MAX_INIT_ARGS+2] = { "init", NULL, }; char * envp_init[MAX_INIT_ENVS+2] = { "HOME=/", "TERM=linux", NULL, }; static const char *panic_later, *panic_param;