On 12/22/2015 02:17 AM, Finn Thain wrote:
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 <fth...@telegraphics.com.au> --- 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 2015-12-22 12:15:51.000000000 +1100 +++ linux/drivers/scsi/NCR5380.c 2015-12-22 12:15:52.000000000 +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 "
Wouldn't it make more sense to remove the USLEEP_WAITLONG completely? From what I can see it is meant to indicate that WAITLONG is enabled, but we've just removed that functionality... Cheers, Hannes -- Dr. Hannes Reinecke zSeries & Storage h...@suse.de +49 911 74053 688 SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg GF: J. Hawn, J. Guild, F. Imendörffer, HRB 16746 (AG Nürnberg) -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
