Daisy chain end detection failed at least with older daisy chain
devices that do not implement the last device signal.
Signed-off-by: Marko Kohtala <[email protected]>
---
drivers/parport/daisy.c | 27 +++++++++++++++++----------
1 files changed, 17 insertions(+), 10 deletions(-)
Index: linux-dvb/drivers/parport/daisy.c
===================================================================
--- linux-dvb.orig/drivers/parport/daisy.c 2005-08-29 20:11:52.000000000 +0300
+++ linux-dvb/drivers/parport/daisy.c 2005-08-29 20:12:35.000000000 +0300
@@ -436,7 +436,7 @@ static int select_port (struct parport *
static int assign_addrs (struct parport *port)
{
- unsigned char s, last_dev;
+ unsigned char s;
unsigned char daisy;
int thisdev = numdevs;
int detected;
@@ -472,10 +472,13 @@ static int assign_addrs (struct parport
}
parport_write_data (port, 0x78); udelay (2);
- last_dev = 0; /* We've just been speaking to a device, so we
- know there must be at least _one_ out there. */
+ s = parport_read_status (port);
- for (daisy = 0; daisy < 4; daisy++) {
+ for (daisy = 0;
+ (s & (PARPORT_STATUS_PAPEROUT|PARPORT_STATUS_SELECT))
+ == (PARPORT_STATUS_PAPEROUT|PARPORT_STATUS_SELECT)
+ && daisy < 4;
+ ++daisy) {
parport_write_data (port, daisy);
udelay (2);
parport_frob_control (port,
@@ -485,14 +488,18 @@ static int assign_addrs (struct parport
parport_frob_control (port, PARPORT_CONTROL_STROBE, 0);
udelay (1);
- if (last_dev)
- /* No more devices. */
- break;
+ add_dev (numdevs++, port, daisy);
- last_dev = !(parport_read_status (port)
- & PARPORT_STATUS_BUSY);
+ /* See if this device thought it was the last in the
+ * chain. */
+ if (!(s & PARPORT_STATUS_BUSY))
+ break;
- add_dev (numdevs++, port, daisy);
+ /* We are seeing pass through status now. We see
+ last_dev from next device or if last_dev does not
+ work status lines from some non-daisy chain
+ device. */
+ s = parport_read_status (port);
}
parport_write_data (port, 0xff); udelay (2);
--
-
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