Commit e62aa046 authored by Ondrej Zary's avatar Ondrej Zary Committed by Linus Torvalds
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paride: pf driver fixes 



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: default avatarOndrej Zary <linux@rainbow-software.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent ba0a7f39

drivers/block/paride/pf.c

+14 −11
Original line number Diff line number Diff line
@@ -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;

	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)

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