Hi Finn,
On Sun, Jan 3, 2016 at 6:05 AM, Finn Thain <fthain@xxxxxxxxxxxxxxxxxxx> wrote:
Allow target selection to fail with a timeout instead of waiting in
infinite loops. This gets rid of the unused NCR_TIMEOUT macro, it is more
defensive and has proved helpful in debugging.
Signed-off-by: Finn Thain <fthain@xxxxxxxxxxxxxxxxxxx>
Reviewed-by: Hannes Reinecke <hare@xxxxxxxx>
Tested-by: Ondrej Zary <linux@xxxxxxxxxxxxxxxxxxxx>
Tested-by: Michael Schmitz <schmitzmic@xxxxxxxxx>
This patch (commit 55500d9b08295e3b6016b53879dea1cb7787f1b0) causes a hang
on ARAnyM with atari_defconfig after:
scsi host0: Atari native SCSI, io_port 0x0, n_io_port 0, base 0x0,
irq 15, can_queue 8, cmd_per_lun 1, sg_tablesize 0, this_id 7, flags {
}, options { REAL_DMA SUPPORT_TAGS }
blk_queue_max_segments: set to minimum 1
--- linux.orig/drivers/scsi/atari_NCR5380.c 2016-01-03 16:03:43.000000000 +1100
+++ linux/drivers/scsi/atari_NCR5380.c 2016-01-03 16:03:44.000000000 +1100
@@ -1436,42 +1437,28 @@ static int NCR5380_select(struct Scsi_Ho
NCR5380_write(OUTPUT_DATA_REG, hostdata->id_mask);
NCR5380_write(MODE_REG, MR_ARBITRATE);
- local_irq_restore(flags);
+ /* The chip now waits for BUS FREE phase. Then after the 800 ns
+ * Bus Free Delay, arbitration will begin.
+ */
- /* Wait for arbitration logic to complete */
-#if defined(NCR_TIMEOUT)
- {
- unsigned long timeout = jiffies + 2*NCR_TIMEOUT;
-
- while (!(NCR5380_read(INITIATOR_COMMAND_REG) & ICR_ARBITRATION_PROGRESS) &&
- time_before(jiffies, timeout) && !hostdata->connected)
- ;
- if (time_after_eq(jiffies, timeout)) {
- printk("scsi : arbitration timeout at %d\n", __LINE__);
+ local_irq_restore(flags);
+ timeout = jiffies + HZ;
+ while (1) {
+ if (time_is_before_jiffies(timeout)) {
NCR5380_write(MODE_REG, MR_BASE);
- NCR5380_write(SELECT_ENABLE_REG, hostdata->id_mask);
+ shost_printk(KERN_ERR, instance,
+ "select: arbitration timeout\n");
return -1;
}
+ if (!(NCR5380_read(MODE_REG) & MR_ARBITRATE)) {
This newly added check always triggers, causing an infinite loop calling
NCR5380_select().
Perhaps this is an ARAnyM quirk?
If not, does it trigger (on some hardware) with drivers/scsi/NCR5380.c, too?
+ /* Reselection interrupt */
+ return -1;
+ }
+ if (NCR5380_read(INITIATOR_COMMAND_REG) & ICR_ARBITRATION_PROGRESS)
+ break;
}
-#else /* NCR_TIMEOUT */
- while (!(NCR5380_read(INITIATOR_COMMAND_REG) & ICR_ARBITRATION_PROGRESS) &&
- !hostdata->connected)
- ;
-#endif
-
- dprintk(NDEBUG_ARBITRATION, "scsi%d: arbitration complete\n", HOSTNO);
-
- if (hostdata->connected) {
- NCR5380_write(MODE_REG, MR_BASE);
- return -1;
- }
- /*
- * The arbitration delay is 2.2us, but this is a minimum and there is
- * no maximum so we can safely sleep for ceil(2.2) usecs to accommodate
- * the integral nature of udelay().
- *
- */
+ /* The SCSI-2 arbitration delay is 2.4 us */
udelay(3);
/* Check for lost arbitration */
On current mainline, this (whitespace-damaged) patch fixed the issue for me:
--- a/drivers/scsi/atari_NCR5380.c
+++ b/drivers/scsi/atari_NCR5380.c
@@ -1253,10 +1253,6 @@ static struct scsi_cmnd *NCR5380_select(struct
Scsi_Host *instance,
INITIATOR_COMMAND_REG, ICR_ARBITRATION_PROGRESS,
ICR_ARBITRATION_PROGRESS, HZ);
spin_lock_irq(&hostdata->lock);
- if (!(NCR5380_read(MODE_REG) & MR_ARBITRATE)) {
- /* Reselection interrupt */
- goto out;
- }
if (err < 0) {
NCR5380_write(MODE_REG, MR_BASE);
shost_printk(KERN_ERR, instance,
@@ -1297,10 +1293,6 @@ static struct scsi_cmnd *NCR5380_select(struct
Scsi_Host *instance,
spin_lock_irq(&hostdata->lock);
- /* NCR5380_reselect() clears MODE_REG after a reselection interrupt */
- if (!(NCR5380_read(MODE_REG) & MR_ARBITRATE))
- goto out;
-
if (!hostdata->selecting) {
NCR5380_write(MODE_REG, MR_BASE);
NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
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