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paride: pf driver fixes

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The pf driver for parallel port floppy drives seems to be broken.  At least
with Imation SuperDisk with EPAT chip, the driver calls pi_connect() and
pi_disconnect after each transferred sector.  At least with EPAT, this
operation is very expensive - causes drive recalibration.  Thus, transferring
even a single byte (dd if=/dev/pf0 of=/dev/null bs=1 count=1) takes 20
seconds, making the driver useless.

The pf_next_buf() function seems to be broken as it returns 1 always (except
when pf_run is non-zero), causing the loop in do_pf_read_drq (and
do_pf_write_drq) to be executed only once.

The following patch fixes this problem.  It also fixes swapped descriptions in
pf_lock() function and removes DBMSG macro, which seems useless.

Signed-off-by: Ondrej Zary <linux@rainbow-software.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Ondrej Zary 2007-11-14 16:59:24 -08:00 committed by Linus Torvalds
parent ba0a7f39ce
commit e62aa046e1
1 changed files with 14 additions and 11 deletions
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25
drivers/block/paride/pf.c
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@ -488,13 +488,11 @@ static int pf_atapi(struct pf_unit *pf, char *cmd, int dlen, char *buf, char *fu
return r;
}
#define DBMSG(msg) ((verbose>1)?(msg):NULL)
static void pf_lock(struct pf_unit *pf, int func)
{
char lo_cmd[12] = { ATAPI_LOCK, pf->lun << 5, 0, 0, func, 0, 0, 0, 0, 0, 0, 0 };
pf_atapi(pf, lo_cmd, 0, pf_scratch, func ? "unlock" : "lock");
pf_atapi(pf, lo_cmd, 0, pf_scratch, func ? "lock" : "unlock");
}
static void pf_eject(struct pf_unit *pf)
@ -555,7 +553,7 @@ static void pf_mode_sense(struct pf_unit *pf)
{ ATAPI_MODE_SENSE, pf->lun << 5, 0, 0, 0, 0, 0, 0, 8, 0, 0, 0 };
char buf[8];
pf_atapi(pf, ms_cmd, 8, buf, DBMSG("mode sense"));
pf_atapi(pf, ms_cmd, 8, buf, "mode sense");
pf->media_status = PF_RW;
if (buf[3] & 0x80)
pf->media_status = PF_RO;
@ -591,7 +589,7 @@ static void pf_get_capacity(struct pf_unit *pf)
char buf[8];
int bs;
if (pf_atapi(pf, rc_cmd, 8, buf, DBMSG("get capacity"))) {
if (pf_atapi(pf, rc_cmd, 8, buf, "get capacity")) {
pf->media_status = PF_NM;
return;
}
@ -804,13 +802,18 @@ static int pf_next_buf(void)
pf_buf += 512;
pf_block++;
if (!pf_run)
return 0;
if (!pf_count)
return 1;
spin_lock_irqsave(&pf_spin_lock, saved_flags);
pf_end_request(1);
spin_unlock_irqrestore(&pf_spin_lock, saved_flags);
return 1;
if (!pf_count) {
spin_lock_irqsave(&pf_spin_lock, saved_flags);
pf_end_request(1);
pf_req = elv_next_request(pf_queue);
spin_unlock_irqrestore(&pf_spin_lock, saved_flags);
if (!pf_req)
return 1;
pf_count = pf_req->current_nr_sectors;
pf_buf = pf_req->buffer;
}
return 0;
}
static inline void next_request(int success)