On Wed, 27 Sep 2006, Guennadi Liakhovetski wrote: > Hi all > > I've got a problem report and a patch from John Adams, he says tmscsim > driver under 2.6.17 and on doesn't allow him to read tapes with blocksize > of 1MB. He fixes this with the below patch. > > On Sun, 24 Sep 2006, John Adams wrote: > > > --- drivers/scsi/tmscsim.c.bak 2006-09-24 12:55:08.000000000 -0400 > > +++ drivers/scsi/tmscsim.c 2006-09-24 12:55:56.000000000 -0400 > > @@ -2300,7 +2300,8 @@ > > .this_id = 7, > > .sg_tablesize = SG_ALL, > > .cmd_per_lun = 1, > > - .use_clustering = DISABLE_CLUSTERING, > > + .use_clustering = ENABLE_CLUSTERING, > > + .max_sectors = 2048, > > }; > > > > /*********************************************************************** > > It looks like > > 1) use_clustering doesn't directly affect maximum block size, so, he > doesn't really need it, although, it might make sense for tmscsim to > improve performance. > > 2) max_sectors is indeed what he needs, but it looks strange that now it > has to be set by the low-level driver... For block devices you can set it > at run time with /sys/block/sda/queue/max_sectors_kb, right? But what > about tapes? > Both 1 and 2 are needed for 1 MB block size. max_sectors_kb for tapes is not visible in /sys. > Sorry, didn't find too much documentation about it. > The limits come from the block subsystem that all scsi devices use nowadays. It is a rather long story but can be found from linux-scsi archives, e.g., http://marc.theaimsgroup.com/?l=linux-scsi&m=114147170831847&w=2 -- Kai - To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
