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MFi386: machdep.c:1.570 clock.c:1.204 by bde: Quick fix for calling DELAY

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for ddb input in some atkbd-based console drivers.  ddb must not use any
normal locks but DELAY() normally calls getit() which needs clock_lock.
This also removes the need for recursion on clock_lock.
This commit is contained in:
peter 2003-09-22 21:56:48 +00:00
parent 9cd1883cc6
commit 202f4eece1
2 changed files with 19 additions and 3 deletions
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2
sys/amd64/amd64/machdep.c
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@ -1166,7 +1166,7 @@ hammer_time(u_int64_t modulep, u_int64_t physfree)
* under witness.
*/
mutex_init();
mtx_init(&clock_lock, "clk", NULL, MTX_SPIN | MTX_RECURSE);
mtx_init(&clock_lock, "clk", NULL, MTX_SPIN);
mtx_init(&icu_lock, "icu", NULL, MTX_SPIN | MTX_NOWITNESS);
/* exceptions */

20
sys/amd64/isa/clock.c
View File

@ -413,8 +413,18 @@ DELAY(int n)
* takes about 1.5 usec for each of the i/o's in getit(). The loop
* takes about 6 usec on a 486/33 and 13 usec on a 386/20. The
* multiplications and divisions to scale the count take a while).
*
* However, if ddb is active then use a fake counter since reading
* the i8254 counter involves acquiring a lock. ddb must not go
* locking for many reasons, but it calls here for at least atkbd
* input.
*/
prev_tick = getit();
#ifdef DDB
if (db_active)
prev_tick = 0;
else
#endif
prev_tick = getit();
n -= 0; /* XXX actually guess no initial overhead */
/*
* Calculate (n * (timer_freq / 1e6)) without using floating point
@ -441,7 +451,13 @@ DELAY(int n)
/ 1000000;
while (ticks_left > 0) {
tick = getit();
#ifdef DDB
if (db_active) {
inb(0x84);
tick = prev_tick + 1;
} else
#endif
tick = getit();
#ifdef DELAYDEBUG
++getit_calls;
#endif