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Add two #ifdef BROKEN_LPT_DELAY's in to the central write byte

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& strobe cycle. These bracket DELAY()'s of BROKEN_LPT_DELAY
microseconds. This can be used to kludge around mysterious hangs and
reboots some users experience. The cause of these failures is still
not known, but is conjectured to be hardware bug originated failures
in the bus cycle.
This commit is contained in:
perry 1999-03-25 02:17:38 +00:00
parent 3db12eddbc
commit 8ade3b61ba
1 changed files with 9 additions and 1 deletions
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10
sys/dev/ic/lpt.c
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@ -1,4 +1,4 @@
/* $NetBSD: lpt.c,v 1.53 1999/02/12 01:51:37 thorpej Exp $ */
/* $NetBSD: lpt.c,v 1.54 1999/03/25 02:17:38 perry Exp $ */
/*
* Copyright (c) 1993, 1994 Charles M. Hannum.
@ -389,7 +389,15 @@ lptintr(arg)
u_char control = sc->sc_control;
/* send char */
bus_space_write_1(iot, ioh, lpt_data, *sc->sc_cp++);
#ifdef BROKEN_LPT_DELAY
/* Kludge to prevent mysterious hangs and reboots. */
DELAY(BROKEN_LPT_DELAY);
#endif
bus_space_write_1(iot, ioh, lpt_control, control | LPC_STROBE);
#ifdef BROKEN_LPT_DELAY
/* Kludge to prevent mysterious hangs and reboots. */
DELAY(BROKEN_LPT_DELAY);
#endif
sc->sc_count--;
bus_space_write_1(iot, ioh, lpt_control, control);
sc->sc_state |= LPT_OBUSY;