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[PATCH v4 18/78] ncr5380: Eliminate USLEEP_WAITLONG delay

From Finn Thain <fthain@telegraphics.com.au>
Newsgroups linux.kernel
Subject [PATCH v4 18/78] ncr5380: Eliminate USLEEP_WAITLONG delay
Date 2016-01-03 06:50 +0100
Message-ID <qMJIe-1kw-11@gated-at.bofh.it> (permalink)
References <qMJfb-148-3@gated-at.bofh.it>
Organization linux.* mail to news gateway

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Linux 2.1.105 introduced the USLEEP_WAITLONG delay, apparently "needed for
Mustek scanners". It is intended to stall the issue queue for 5 seconds.
There are a number of problems with this.

1. Only g_NCR5380 enables the delay, which implies that the other five
   drivers using the NCR5380.c core driver remain incompatible with
   Mustek scanners.

2. The delay is not implemented by atari_NCR5380.c, which is problematic
   for re-unifying the two core driver forks.

3. The delay is implemented using NCR5380_set_timer() which makes it
   unreliable. A new command queued by the mid-layer cancels the delay.

4. The delay is applied indiscriminately in several situations in which
   NCR5380_select() returns -1. These are-- reselection by the target,
   failure of the target to assert BSY, and failure of the target to
   assert REQ. It's clear from the comments that USLEEP_WAITLONG is not
   relevant to the reselection case. And reportedly, these scanners do
   not disconnect.

5. atari_NCR5380.c was forked before Linux 2.1.105, so it was spared some
   of the damage done to NCR5380.c. In this case, the atari_NCR5380.c core
   driver was more standard-compliant and may not have needed any
   workaround like the USLEEP_WAITLONG kludge. The compliance issue was
   addressed in the previous patch.

If these scanners still don't work, we need a better solution. Retrying
selection until EH aborts a command offers equivalent robustness. Bugs in
the existing driver prevent EH working correctly but this is addressed in
a subsequent patch. Remove USLEEP_WAITLONG.

Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Tested-by: Ondrej Zary <linux@rainbow-software.org>

---
 drivers/scsi/NCR5380.c   |   19 +++++--------------
 drivers/scsi/g_NCR5380.c |    1 -
 2 files changed, 5 insertions(+), 15 deletions(-)

Index: linux/drivers/scsi/NCR5380.c
===================================================================
--- linux.orig/drivers/scsi/NCR5380.c	2016-01-03 16:03:19.000000000 +1100
+++ linux/drivers/scsi/NCR5380.c	2016-01-03 16:03:20.000000000 +1100
@@ -468,10 +468,6 @@ static void NCR5380_print_phase(struct S
 #ifndef USLEEP_POLL
 #define USLEEP_POLL msecs_to_jiffies(200)
 #endif
-#ifndef USLEEP_WAITLONG
-/* RvC: (reasonable time to wait on select error) */
-#define USLEEP_WAITLONG USLEEP_SLEEP
-#endif
 
 /* 
  * Function : int should_disconnect (unsigned char cmd)
@@ -619,8 +615,8 @@ static void prepare_info(struct Scsi_Hos
 	         "can_queue %d, cmd_per_lun %d, "
 	         "sg_tablesize %d, this_id %d, "
 	         "flags { %s%s%s%s}, "
-#if defined(USLEEP_POLL) && defined(USLEEP_WAITLONG)
-		 "USLEEP_POLL %lu, USLEEP_WAITLONG %lu, "
+#if defined(USLEEP_POLL) && defined(USLEEP_SLEEP)
+		 "USLEEP_POLL %lu, USLEEP_SLEEP %lu, "
 #endif
 	         "options { %s} ",
 	         instance->hostt->name, instance->io_port, instance->n_io_port,
@@ -631,8 +627,8 @@ static void prepare_info(struct Scsi_Hos
 	         hostdata->flags & FLAG_DTC3181E      ? "DTC3181E "      : "",
 	         hostdata->flags & FLAG_NO_PSEUDO_DMA ? "NO_PSEUDO_DMA " : "",
 	         hostdata->flags & FLAG_TOSHIBA_DELAY ? "TOSHIBA_DELAY "  : "",
-#if defined(USLEEP_POLL) && defined(USLEEP_WAITLONG)
-	         USLEEP_POLL, USLEEP_WAITLONG,
+#if defined(USLEEP_POLL) && defined(USLEEP_SLEEP)
+	         USLEEP_POLL, USLEEP_SLEEP,
 #endif
 #ifdef AUTOPROBE_IRQ
 	         "AUTOPROBE_IRQ "
@@ -1030,15 +1026,10 @@ static void NCR5380_main(struct work_str
 			if (!NCR5380_select(instance, tmp)) {
 				/* OK or bad target */
 			} else {
-				/* RvC: device failed, so we wait a long time
-				   this is needed for Mustek scanners, that
-				   do not respond to commands immediately
-				   after a scan */
-				printk(KERN_DEBUG "scsi%d: device %d did not respond in time\n", instance->host_no, tmp->device->id);
 				LIST(tmp, hostdata->issue_queue);
 				tmp->host_scribble = (unsigned char *) hostdata->issue_queue;
 				hostdata->issue_queue = tmp;
-				NCR5380_set_timer(hostdata, USLEEP_WAITLONG);
+				done = 0;
 			}
 		}	/* if hostdata->selecting */
 		if (hostdata->connected
Index: linux/drivers/scsi/g_NCR5380.c
===================================================================
--- linux.orig/drivers/scsi/g_NCR5380.c	2016-01-03 16:03:06.000000000 +1100
+++ linux/drivers/scsi/g_NCR5380.c	2016-01-03 16:03:20.000000000 +1100
@@ -59,7 +59,6 @@
 /* settings for DTC3181E card with only Mustek scanner attached */
 #define USLEEP_POLL	msecs_to_jiffies(10)
 #define USLEEP_SLEEP	msecs_to_jiffies(200)
-#define USLEEP_WAITLONG	msecs_to_jiffies(5000)
 
 #define AUTOPROBE_IRQ
 


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Thread

[PATCH v4 00/78] More fixes, cleanup and modernization for NCR5380 drivers Finn Thain <fthain@telegraphics.com.au> - 2016-01-03 06:20 +0100
  [PATCH v4 63/78] atari_NCR5380: Remove HOSTNO macro from printk() and seq_printf() calls Finn Thain <fthain@telegraphics.com.au> - 2016-01-03 06:30 +0100
  [PATCH v4 29/78] ncr5380: Remove references to linked commands Finn Thain <fthain@telegraphics.com.au> - 2016-01-03 06:30 +0100
  [PATCH v4 73/78] ncr5380: Fix pseudo DMA transfers on 53C400 Finn Thain <fthain@telegraphics.com.au> - 2016-01-03 06:30 +0100
  [PATCH v4 21/78] ncr5380: Sleep when polling, if possible Finn Thain <fthain@telegraphics.com.au> - 2016-01-03 06:30 +0100
  [PATCH v4 33/78] atari_NCR5380: Set do_abort() timeouts Finn Thain <fthain@telegraphics.com.au> - 2016-01-03 06:30 +0100
  [PATCH v4 53/78] ncr5380: Use shost_priv helper Finn Thain <fthain@telegraphics.com.au> - 2016-01-03 06:30 +0100
  [PATCH v4 62/78] ncr5380: Implement new eh_bus_reset_handler Finn Thain <fthain@telegraphics.com.au> - 2016-01-03 06:30 +0100
  [PATCH v4 60/78] ncr5380: Implement new eh_abort_handler Finn Thain <fthain@telegraphics.com.au> - 2016-01-03 06:30 +0100
  [PATCH v4 51/78] ncr5380: Remove command list debug code Finn Thain <fthain@telegraphics.com.au> - 2016-01-03 06:30 +0100
  [PATCH v4 68/78] ncr5380: Fix trailing whitespace using regexp Finn Thain <fthain@telegraphics.com.au> - 2016-01-03 06:30 +0100
  [PATCH v4 38/78] ncr5380: Remove UNSAFE macro Finn Thain <fthain@telegraphics.com.au> - 2016-01-03 06:30 +0100
  [PATCH v4 46/78] ncr5380: Fix NDEBUG_NO_DATAOUT flag Finn Thain <fthain@telegraphics.com.au> - 2016-01-03 06:30 +0100
  [PATCH v4 47/78] ncr5380: Fix and cleanup scsi_host_template initializers Finn Thain <fthain@telegraphics.com.au> - 2016-01-03 06:30 +0100
  [PATCH v4 44/78] ncr5380: Fix off-by-one bug in extended_msg[] bounds check Finn Thain <fthain@telegraphics.com.au> - 2016-01-03 06:30 +0100
  [PATCH v4 55/78] ncr5380: Remove LIST and REMOVE macros Finn Thain <fthain@telegraphics.com.au> - 2016-01-03 06:30 +0100
  [PATCH v4 69/78] ncr5380: Fix whitespace in comments using regexp Finn Thain <fthain@telegraphics.com.au> - 2016-01-03 06:30 +0100
    Re: [PATCH v4 69/78] ncr5380: Fix whitespace in comments using  regexp Joe Perches <joe@perches.com> - 2016-01-03 09:00 +0100
      Re: [PATCH v4 69/78] ncr5380: Fix whitespace in comments using  regexp Finn Thain <fthain@telegraphics.com.au> - 2016-01-03 09:20 +0100
      Re: [PATCH v4 69/78] ncr5380: Fix whitespace in comments using  regexp One Thousand Gnomes <gnomes@lxorguk.ukuu.org.uk> - 2016-01-03 15:20 +0100
        Re: [PATCH v4 69/78] ncr5380: Fix whitespace in comments using  regexp Joe Perches <joe@perches.com> - 2016-01-03 19:30 +0100
          Re: [PATCH v4 69/78] ncr5380: Fix whitespace in comments using  regexp One Thousand Gnomes <gnomes@lxorguk.ukuu.org.uk> - 2016-01-03 22:40 +0100
            Re: [PATCH v4 69/78] ncr5380: Fix whitespace in comments using  regexp Joe Perches <joe@perches.com> - 2016-01-03 22:50 +0100
              Re: [PATCH v4 69/78] ncr5380: Fix whitespace in comments using  regexp Joe Perches <joe@perches.com> - 2016-01-03 23:20 +0100
  [PATCH v4 71/78] atari_NCR5380: Merge changes from NCR5380.c Finn Thain <fthain@telegraphics.com.au> - 2016-01-03 06:30 +0100
  [PATCH v4 70/78] ncr5380: Merge changes from atari_NCR5380.c Finn Thain <fthain@telegraphics.com.au> - 2016-01-03 06:30 +0100
  [PATCH v4 52/78] ncr5380: Remove H_NO macro and introduce dsprintk Finn Thain <fthain@telegraphics.com.au> - 2016-01-03 06:30 +0100
  [PATCH v4 31/78] ncr5380: Fix !REQ timeout in do_abort() Finn Thain <fthain@telegraphics.com.au> - 2016-01-03 06:30 +0100
  [PATCH v4 74/78] ncr5380: Use runtime register mapping Finn Thain <fthain@telegraphics.com.au> - 2016-01-03 06:30 +0100
  [PATCH v4 76/78] ncr5380: Enable PDMA for DTC chips Finn Thain <fthain@telegraphics.com.au> - 2016-01-03 06:30 +0100
  [PATCH v4 67/78] ncr5380: Cleanup comments Finn Thain <fthain@telegraphics.com.au> - 2016-01-03 06:30 +0100
  [PATCH v4 39/78] ncr5380: Standardize interrupt handling Finn Thain <fthain@telegraphics.com.au> - 2016-01-03 06:30 +0100
  [PATCH v4 65/78] atari_scsi, sun3_scsi: Remove global Scsi_Host pointer Finn Thain <fthain@telegraphics.com.au> - 2016-01-03 06:30 +0100
  [PATCH v4 57/78] ncr5380: Use standard list data structure Finn Thain <fthain@telegraphics.com.au> - 2016-01-03 06:30 +0100
  [PATCH v4 42/78] ncr5380: Replace READ_OVERRUNS macro with FLAG_NO_DMA_FIXUPS Finn Thain <fthain@telegraphics.com.au> - 2016-01-03 06:30 +0100
  [PATCH v4 56/78] ncr5380: Remove redundant volatile qualifiers Finn Thain <fthain@telegraphics.com.au> - 2016-01-03 06:30 +0100
  [PATCH v4 59/78] ncr5380: Fix autosense bugs Finn Thain <fthain@telegraphics.com.au> - 2016-01-03 06:30 +0100
  [PATCH v4 45/78] ncr5380: Cleanup #include directives Finn Thain <fthain@telegraphics.com.au> - 2016-01-03 06:30 +0100
  [PATCH v4 75/78] ncr5380: Enable PDMA for NCR53C400A Finn Thain <fthain@telegraphics.com.au> - 2016-01-03 06:30 +0100
  [PATCH v4 48/78] atari_NCR5380: Fix queue_size limit Finn Thain <fthain@telegraphics.com.au> - 2016-01-03 06:30 +0100
  [PATCH v4 54/78] ncr5380: Use dsprintk() for queue debugging Finn Thain <fthain@telegraphics.com.au> - 2016-01-03 06:30 +0100
  [PATCH v4 08/78] ncr5380: Move NCR53C400-specific code Finn Thain <fthain@telegraphics.com.au> - 2016-01-03 06:30 +0100
  [PATCH v4 35/78] ncr5380: Dont wait for BUS FREE after disconnect Finn Thain <fthain@telegraphics.com.au> - 2016-01-03 06:30 +0100
  [PATCH v4 10/78] atari_NCR5380: Remove RESET_BOOT, CONFIG_ATARI_SCSI_TOSHIBA_DELAY and CONFIG_ATARI_SCSI_RESET_BOOT Finn Thain <fthain@telegraphics.com.au> - 2016-01-03 06:30 +0100
  [PATCH v4 58/78] ncr5380: Refactor command completion Finn Thain <fthain@telegraphics.com.au> - 2016-01-03 06:30 +0100
  [PATCH v4 64/78] atari_NCR5380: Eliminate HOSTNO macro Finn Thain <fthain@telegraphics.com.au> - 2016-01-03 06:30 +0100
  [PATCH v4 78/78] ncr5380: Add support for HP C2502 Finn Thain <fthain@telegraphics.com.au> - 2016-01-03 06:30 +0100
  [PATCH v4 72/78] ncr5380: Cleanup whitespace and parentheses Finn Thain <fthain@telegraphics.com.au> - 2016-01-03 06:30 +0100
  [PATCH v4 77/78] ncr5380: Fix wait for 53C80 registers registers after PDMA Finn Thain <fthain@telegraphics.com.au> - 2016-01-03 06:30 +0100
  [PATCH v4 61/78] ncr5380: Fix EH during arbitration and selection Finn Thain <fthain@telegraphics.com.au> - 2016-01-03 06:30 +0100
  [PATCH v4 03/78] ncr5380: Eliminate PDEBUG*, TDEBUG* and DTCDEBUG* macros Finn Thain <fthain@telegraphics.com.au> - 2016-01-03 06:30 +0100
  [PATCH v4 66/78] ncr5380: Fix soft lockups Finn Thain <fthain@telegraphics.com.au> - 2016-01-03 06:30 +0100
  [PATCH v4 32/78] ncr5380: Fix bus phase in do_abort() Finn Thain <fthain@telegraphics.com.au> - 2016-01-03 06:40 +0100
  [PATCH v4 06/78] ncr5380: Remove NCR5380_instance_name macro Finn Thain <fthain@telegraphics.com.au> - 2016-01-03 06:40 +0100
  [PATCH v4 34/78] atari_NCR5380: Use arbitration timeout Finn Thain <fthain@telegraphics.com.au> - 2016-01-03 06:40 +0100
  [PATCH v4 50/78] ncr5380: Change instance->host_lock to hostdata->lock Finn Thain <fthain@telegraphics.com.au> - 2016-01-03 06:40 +0100
  [PATCH v4 22/78] ncr5380: Eliminate selecting state Finn Thain <fthain@telegraphics.com.au> - 2016-01-03 06:40 +0100
  [PATCH v4 27/78] ncr5380: Add missing lock in eh_abort_handler Finn Thain <fthain@telegraphics.com.au> - 2016-01-03 06:40 +0100
  [PATCH v4 20/78] ncr5380: Introduce unbound workqueue Finn Thain <fthain@telegraphics.com.au> - 2016-01-03 06:40 +0100
  [PATCH v4 11/78] ncr5380: Simplify bus reset handlers Finn Thain <fthain@telegraphics.com.au> - 2016-01-03 06:40 +0100
  [PATCH v4 17/78] ncr5380: Keep BSY asserted when entering SELECTION phase Finn Thain <fthain@telegraphics.com.au> - 2016-01-03 06:40 +0100
  [PATCH v4 05/78] ncr5380: Remove NCR5380_local_declare and NCR5380_setup macros Finn Thain <fthain@telegraphics.com.au> - 2016-01-03 06:40 +0100
  [PATCH v4 37/78] ncr5380: Standardize work queueing algorithm Finn Thain <fthain@telegraphics.com.au> - 2016-01-03 06:40 +0100
  [PATCH v4 12/78] ncr5380: Remove unused hostdata->aborted flag Finn Thain <fthain@telegraphics.com.au> - 2016-01-03 06:40 +0100
  [PATCH v4 49/78] ncr5380: Remove redundant ICR_ARBITRATION_LOST test and eliminate FLAG_DTC3181E Finn Thain <fthain@telegraphics.com.au> - 2016-01-03 06:40 +0100
  [PATCH v4 28/78] ncr5380: Drop DEF_SCSI_QCMD macro Finn Thain <fthain@telegraphics.com.au> - 2016-01-03 06:40 +0100
  [PATCH v4 40/78] ncr5380: Introduce NCR5380_poll_politely2 Finn Thain <fthain@telegraphics.com.au> - 2016-01-03 06:40 +0100
  [PATCH v4 30/78] ncr5380: Add missing break after case MESSAGE_REJECT Finn Thain <fthain@telegraphics.com.au> - 2016-01-03 06:40 +0100
  [PATCH v4 43/78] ncr5380: Standardize reselection handling Finn Thain <fthain@telegraphics.com.au> - 2016-01-03 06:40 +0100
  [PATCH v4 26/78] ncr5380: Fix NCR5380_transfer_pio() result Finn Thain <fthain@telegraphics.com.au> - 2016-01-03 06:40 +0100
  [PATCH v4 19/78] ncr5380: Cleanup bogus {request,release}_region() calls Finn Thain <fthain@telegraphics.com.au> - 2016-01-03 06:40 +0100
  [PATCH v4 07/78] ncr5380: Split NCR5380_init() into two functions Finn Thain <fthain@telegraphics.com.au> - 2016-01-03 06:40 +0100
  [PATCH v4 36/78] ncr5380: Use work_struct instead of delayed_work Finn Thain <fthain@telegraphics.com.au> - 2016-01-03 06:40 +0100
  [PATCH v4 25/78] ncr5380: Rework disconnect versus poll logic Finn Thain <fthain@telegraphics.com.au> - 2016-01-03 06:40 +0100
  [PATCH v4 09/78] atari_NCR5380: Reset bus on driver initialization if required Finn Thain <fthain@telegraphics.com.au> - 2016-01-03 06:40 +0100
  [PATCH v4 41/78] ncr5380: Replace redundant flags with FLAG_NO_DMA_FIXUP Finn Thain <fthain@telegraphics.com.au> - 2016-01-03 06:40 +0100
  [PATCH v4 15/78] ncr5380: Always escalate bad target time-out in NCR5380_select() Finn Thain <fthain@telegraphics.com.au> - 2016-01-03 06:50 +0100
  [PATCH v4 01/78] atari_scsi: Fix SCSI host ID setting Finn Thain <fthain@telegraphics.com.au> - 2016-01-03 06:50 +0100
  [PATCH v4 16/78] ncr5380: Proceed with next command after NCR5380_select() calls scsi_done Finn Thain <fthain@telegraphics.com.au> - 2016-01-03 06:50 +0100
  [PATCH v4 14/78] ncr5380: Use return instead of goto in NCR5380_select() Finn Thain <fthain@telegraphics.com.au> - 2016-01-03 06:50 +0100
  [PATCH v4 04/78] ncr5380: Remove more pointless macros Finn Thain <fthain@telegraphics.com.au> - 2016-01-03 06:50 +0100
  [PATCH v4 18/78] ncr5380: Eliminate USLEEP_WAITLONG delay Finn Thain <fthain@telegraphics.com.au> - 2016-01-03 06:50 +0100
  [PATCH v4 02/78] ncr5380: Remove redundant static variable initializers Finn Thain <fthain@telegraphics.com.au> - 2016-01-03 06:50 +0100
  Re: [PATCH v4 00/78] More fixes, cleanup and modernization for NCR5380 drivers "Martin K. Petersen" <martin.petersen@oracle.com> - 2016-01-07 04:00 +0100

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