Date: Wed, 30 Sep 1998 11:49:12 -0600 (MDT) From: "Justin T. Gibbs" <gibbs@narnia.plutotech.com> To: Karl Denninger <karl@denninger.net> Cc: scsi@FreeBSD.ORG Subject: Re: Long IDE probes? Message-ID: <199809301749.LAA24440@narnia.plutotech.com>
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> SCSI devices similarly are probed by the adapter BIOS. Again, there is no > reason for the long wait that I can fathom. Then you don't fathom SCSI. When the system comes up, it resets the SCSI bus to ensure that all previously negotiated transfer negotiations have been nullified. Some devices take longer than others to respond after a bus reset. If you are dealing with modern disks, you only need to wait ~100ms. If you are dealing with tape drives, some cdrom drives, or older devices, you must wait longer or risk "not seeing" the device. The bus settle delay is easily configurable so that people with nice devices can shorten it, but the default delay in GENERIC is there for a very good reason. -- Justin To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-scsi" in the body of the message
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