Date: Mon, 23 Sep 2002 14:40:06 -0700 (PDT) From: Matthew Jacob <mjacob@feral.com> To: "Kenneth D. Merry" <ken@kdm.org> Cc: Brooks Davis <brooks@one-eyed-alien.net>, scsi@FreeBSD.ORG Subject: Re: cvs commit: src/sys/cam/scsi scsi_all.c Message-ID: <Pine.BSF.4.21.0209231439440.637-100000@beppo> In-Reply-To: <20020923153407.A38651@panzer.kdm.org>
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On Mon, 23 Sep 2002, Kenneth D. Merry wrote: > On Mon, Sep 23, 2002 at 14:19:31 -0700, Brooks Davis wrote: > > On Mon, Sep 23, 2002 at 01:59:48PM -0700, Matthew Jacob wrote: > > > > > > But you did, in fact, change the default behaviour in that SCSI_DELAY=0 > > > had been an accepted config option before. I've restored the ability to > > > do this. And I am in no way shooting myself in the foot- that claim on > > > your part is unnecessary and misplaced. In a system with 144 PCI slots, > > > e.g,, should we ever install FreeBSD on an alpha 8400 and fill it full > > > of either Fibre Channel cards, or with SCSI cards that are connected to > > > anything more modern than 1992 and more pricey than a UMASS device, I'd > > > like to have it finish booting this year. > > > > > > I don't think it's particularly important to be able use the tunable to > > > set back down to zero as long as those of us who need to make the > > > behaviour more acceptable for high end system can do so. > > > > When I looked at the code again, I realized there is one reason to want > > to be able to set it to zero which is that the check is now applied to > > boot time (in init_scsi_delay()) so is you set SCSI_DELAY=0 you get > > SCSI_DELAY=SCSI_MIN_DELAY even if if you compile it in. Given you > > example above, maybe we should just remove the checks entierly since in > > the current configuration you would have 14.4sec of delay (not hugh, but > > perhaps undesirably large). > > > > My comment about footshooting was refering to removing the attempt to > > keep people from trying to set the value in seconds, not that you were > > doing it to yourself. I'm fully aware you know more about scsi them > > I'm, ever likely to. :) > > I think we should leave the restriction in place for now. It's far more > likely that someone will think that SCSI_DELAY is set in seconds, and set > it to something between 0 and 100, which can cause problems on parallel > SCSI busses. > > Keep in mind that the delay is not serialized, it is applied to all busses > in parallel. If you set SCSI_DELAY to 15000, you get 15 seconds of delay, > no matter how many busses are in the system. Oh, yea, that's right. In any case, I totally disagree. Let us specify a 0 delay if we want to. Thank you. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-scsi" in the body of the message
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