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Parallel Port Direction Fix

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The direction bit in the control register should not be directly

set using PPWCONTROL. The kernel gives the following debug message.

    parport0 (ppdev0): use data_reverse for this!

More over setting the data pins to forward mode does not work,
perhaps a bug in the Linux PP driver. The right way to do this is
to use PPDATADIR to set the direction. The patch checks if the
user is toggling the direction bit, and invokes PPDATADIR to
do the job.

Signed-off-by: Vijay Kumar B <vijaykumar@bravegnu.org>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>

git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@5063 c046a42c-6fe2-441c-8c8c-71466251a162
This commit is contained in:
aurel32 2008-08-22 08:57:09 +00:00
parent f34af52c53
commit 563e3c6e6e
3 changed files with 17 additions and 0 deletions
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12
hw/parallel.c
View file

@ -129,6 +129,7 @@ static void parallel_ioport_write_hw(void *opaque, uint32_t addr, uint32_t val)
{
ParallelState *s = opaque;
uint8_t parm = val;
int dir;
/* Sometimes programs do several writes for timing purposes on old
HW. Take care not to waste time on writes that do nothing. */
@ -154,6 +155,17 @@ static void parallel_ioport_write_hw(void *opaque, uint32_t addr, uint32_t val)
if (s->control == val)
return;
pdebug("wc%02x\n", val);
if ((val & PARA_CTR_DIR) != (s->control & PARA_CTR_DIR)) {
if (val & PARA_CTR_DIR) {
dir = 1;
} else {
dir = 0;
}
qemu_chr_ioctl(s->chr, CHR_IOCTL_PP_DATA_DIR, &dir);
parm &= ~PARA_CTR_DIR;
}
qemu_chr_ioctl(s->chr, CHR_IOCTL_PP_WRITE_CONTROL, &parm);
s->control = val;
break;

1
qemu-char.h
View file

@ -27,6 +27,7 @@ typedef struct {
#define CHR_IOCTL_PP_EPP_READ 9
#define CHR_IOCTL_PP_EPP_WRITE_ADDR 10
#define CHR_IOCTL_PP_EPP_WRITE 11
#define CHR_IOCTL_PP_DATA_DIR 12
#define CHR_IOCTL_SERIAL_SET_TIOCM 12
#define CHR_IOCTL_SERIAL_GET_TIOCM 13

4
vl.c
View file

@ -2835,6 +2835,10 @@ static int pp_ioctl(CharDriverState *chr, int cmd, void *arg)
return -ENOTSUP;
*(uint8_t *)arg = b;
break;
case CHR_IOCTL_PP_DATA_DIR:
if (ioctl(fd, PPDATADIR, (int *)arg) < 0)
return -ENOTSUP;
break;
case CHR_IOCTL_PP_EPP_READ_ADDR:
if (pp_hw_mode(drv, IEEE1284_MODE_EPP|IEEE1284_ADDR)) {
struct ParallelIOArg *parg = arg;