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Work around a braindead signal handling in many newer HP printers.

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They don't have BUSY de-asserted by the time they ACK (and thus cause
an interrupt).  The workaround is to try seeing if the BUSY will be
de-asserted soon, and if not, to use an incremental backoff and
semi-polled mode instead of the fixed timeout with 1/2 s we've been
using previously (that caused the printer to run really slooow).

Printers that have been working previously should not be affected by
this.
This commit is contained in:
joerg 1996-04-04 12:28:36 +00:00
parent 0ca25fdf42
commit cd6ca108de
1 changed files with 26 additions and 8 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

34
sys/i386/isa/lpt.c
View File

@ -46,7 +46,7 @@
* SUCH DAMAGE.
*
* from: unknown origin, 386BSD 0.1
* $Id: lpt.c,v 1.51 1996/03/28 14:28:44 scrappy Exp $
* $Id: lpt.c,v 1.52 1996/03/29 11:54:56 bde Exp $
*/
/*
@ -149,7 +149,8 @@
#define LPINITRDY 4 /* wait up to 4 seconds for a ready */
#define LPTOUTTIME 4 /* wait up to 4 seconds for a ready */
#define LPTOUTINITIAL 10 /* initial timeout to wait for ready 1/10 s */
#define LPTOUTMAX 1 /* maximal timeout 1 s */
#define LPPRI (PZERO+8)
#define BUFSIZE 1024
@ -221,6 +222,7 @@ static struct lpt_softc {
#define LP_HAS_IRQ 0x01 /* we have an irq available */
#define LP_USE_IRQ 0x02 /* we are using our irq */
#define LP_ENABLE_IRQ 0x04 /* enable IRQ on open */
u_char sc_backoff ; /* time to call lptout() again */
#ifdef INET
struct ifnet sc_if;
@ -590,7 +592,8 @@ lptopen (dev_t dev, int flags, int fmt, struct proc *p)
lprintf("irq %x\n", sc->sc_irq);
if (sc->sc_irq & LP_USE_IRQ) {
sc->sc_state |= TOUT;
timeout ((timeout_func_t)lptout, (caddr_t)sc, hz/2);
timeout ((timeout_func_t)lptout, (caddr_t)sc,
(sc->sc_backoff = hz/LPTOUTINITIAL));
}
lprintf("opened.\n");
@ -602,9 +605,12 @@ lptout (struct lpt_softc * sc)
{ int pl;
lprintf ("T %x ", inb(sc->sc_port+lpt_status));
if (sc->sc_state & OPEN)
timeout ((timeout_func_t)lptout, (caddr_t)sc, hz/2);
else
if (sc->sc_state & OPEN) {
sc->sc_backoff++;
if (sc->sc_backoff > hz/LPTOUTMAX)
sc->sc_backoff = sc->sc_backoff > hz/LPTOUTMAX;
timeout ((timeout_func_t)lptout, (caddr_t)sc, sc->sc_backoff);
} else
sc->sc_state &= ~TOUT;
if (sc->sc_state & ERROR)
@ -785,6 +791,7 @@ lptintr(int unit)
{
struct lpt_softc *sc = lpt_sc + unit;
int port = sc->sc_port, sts;
int i;
#ifdef INET
if(sc->sc_if.if_flags & IFF_UP) {
@ -793,9 +800,19 @@ lptintr(int unit)
}
#endif /* INET */
/* is printer online and ready for output */
if (((sts=inb(port+lpt_status)) & RDY_MASK) == LP_READY) {
/*
* Is printer online and ready for output?
*
* Avoid falling back to lptout() too quickly. First spin-loop
* to see if the printer will become ready ``really soon now''.
*/
for (i = 0;
i < 100 &&
((sts=inb(port+lpt_status)) & RDY_MASK) != LP_READY;
i++) ;
if ((sts & RDY_MASK) == LP_READY) {
sc->sc_state = (sc->sc_state | OBUSY) & ~ERROR;
sc->sc_backoff = hz/LPTOUTINITIAL;
if (sc->sc_xfercnt) {
/* send char */
@ -822,6 +839,7 @@ lptintr(int unit)
if(((sts & (LPS_NERR | LPS_OUT) ) != LPS_NERR) &&
(sc->sc_state & OPEN))
sc->sc_state |= ERROR;
/* lptout() will jump in and try to restart. */
}
lprintf("sts %x ", sts);
}