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Add a new loader(8) variable, twiddle_divisor, allowing control over the

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output frequency of the "twiddle" IO progress indicator.  The default
value is 1.  For larger values N, the next stage of the animation is only
output on every Nth call to the output routine.  A sufficiently large N
effectively disables the animation completely.
This commit is contained in:
Ian Lepore 2014-12-22 22:07:22 +00:00
parent 7e654612dc
commit af3cafd76c
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=276087
3 changed files with 37 additions and 1 deletions
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29
sys/boot/common/console.c
View File

@ -39,6 +39,7 @@ static int cons_set(struct env_var *ev, int flags, const void *value);
static int cons_find(const char *name);
static int cons_check(const char *string);
static void cons_change(const char *string);
static int twiddle_set(struct env_var *ev, int flags, const void *value);
/*
* Detect possible console(s) to use. If preferred console(s) have been
@ -52,6 +53,9 @@ cons_probe(void)
int active;
char *prefconsole;
/* We want a callback to install the new value when this var changes. */
env_setenv("twiddle_divisor", EV_VOLATILE, "1", twiddle_set, env_nounset);
/* Do all console probes */
for (cons = 0; consoles[cons] != NULL; cons++) {
consoles[cons]->c_flags = 0;
@ -232,3 +236,28 @@ cons_change(const char *string)
free(dup);
}
/*
* Change the twiddle divisor.
*
* The user can set the twiddle_divisor variable to directly control how fast
* the progress twiddle spins, useful for folks with slow serial consoles. The
* code to monitor changes to the variable and propagate them to the twiddle
* routines has to live somewhere. Twiddling is console-related so it's here.
*/
static int
twiddle_set(struct env_var *ev, int flags, const void *value)
{
u_long tdiv;
char * eptr;
tdiv = strtoul(value, &eptr, 0);
if (*(const char *)value == 0 || *eptr != 0) {
printf("invalid twiddle_divisor '%s'\n", (const char *)value);
return (CMD_ERROR);
}
twiddle_divisor((u_int)tdiv);
env_setenv(ev->ev_name, flags | EV_NOHOOK, value, NULL, NULL);
return(CMD_OK);
}

8
sys/boot/common/loader.8
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@ -24,7 +24,7 @@
.\"
.\" $FreeBSD$
.\"
.Dd October 1, 2013
.Dd December 22, 2014
.Dt LOADER 8
.Os
.Sh NAME
@ -670,6 +670,12 @@ Overrides the compile-time set value of
.Dv TCBHASHSIZE
or the preset default of 512.
Must be a power of 2.
.It Va twiddle_divisor
Throttles the output of the `twiddle' I/O progress indicator displayed
while loading the kernel and modules.
This is useful on slow serial consoles where the time spent waiting for
these characters to be written can add up to many seconds.
The default is 1 (full speed); a value of 2 spins half as fast, and so on.
.It Va vm.kmem_size
Sets the size of kernel memory (bytes).
This overrides the value determined when the kernel was compiled.

1
sys/boot/forth/loader.conf
View File

@ -75,6 +75,7 @@ module_path="/boot/modules" # Set the module search path
# the block size is set to 512. If the value
# is out of range ( < 8 || > 9008 ) an error is
# returned.
#twiddle_divisor="1" # >1 means slow down the progress indicator.
##############################################################