Hello,
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.
--
Ondrej Zary
--- linux-2.6.23-orig/drivers/block/paride/pf.c 2007-10-09 22:31:38.000000000
+0200
+++ linux/drivers/block/paride/pf.c 2007-11-08 22:29:31.000000000 +0100
@@ -488,13 +488,11 @@
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 @@
{ 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 @@
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 @@
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)
-
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