Date: Thu, 25 Feb 1999 18:07:39 +0100 From: Ladavac Marino <mladavac@metropolitan.at> To: 'Sheldon Hearn' <sheldonh@iafrica.com>, Pierre Beyssac <beyssac@enst.fr> Cc: Greg Lehey <grog@lemis.com>, freebsd-current@FreeBSD.ORG Subject: RE: IDE CDROM not found with PIIX4 chipset, -current kernel Message-ID: <97A8CA5BF490D211A94F0000F6C2E55D09754E@s-lmh-wi-900.corpnet.at>
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> -----Original Message----- > From: Sheldon Hearn [SMTP:sheldonh@iafrica.com] > Sent: Thursday, February 25, 1999 5:40 PM > To: Pierre Beyssac > Cc: Greg Lehey; freebsd-current@FreeBSD.ORG > Subject: Re: IDE CDROM not found with PIIX4 chipset, -current > kernel > > > > On Thu, 25 Feb 1999 17:16:53 +0100, Pierre Beyssac wrote: > > > I tried to find out why it worked with a Linux kernel by comparing > > our IDE code and theirs, but it was way beyond my comprehension. > > I'm not trained for the black magic of IDE probing. > > I used this particular issue for the launch of my first adventure into > serial console kernel debugging. Multo fun. > > I can offer you two interesting points: > > 1) I have an ATAPI drive that FreeBSD 2.2-STABLE won't detect on boot > if > it contains a disc. > > 2) I found that stepping through the kernel caused exactly the same > problems I was having with accessing my one ATAPI drive that I > experience just running normally with my other drive. So it looks > like at least one problem regarding ATAPI has to do with timings. > > So far, the conversations I've had with clueful FreeBSD hackers have > led > me to accept the following: > > A) The ATAPI standard is weak and the variety of implimentations > thereof > is even worse. > > B) The odds that your ATAPI CDROM drive will behave predictably in > accordance with said standards are directly proportional to its > age. > It seems that newer (24xspeed+) drives suck. > > C) The ATAPI code in FreeBSD is about as good as our hackers care to > make it, given the demotivating impact of A and B above. > > I spent a good few days stepping around my kernel over serial > connection, using a "working" 4xspeed drive and a "broken" 36xspeed > drive and testing a reproducible fault with cdcontrol. I'm a pretty > stubborn guy, but I gave up. [ML] Heh, it would seem that the prevailing OS is not really ATAPI compliant and the manufacturers try to make their hardware more easily detectable for the prevailing OS family. How about this "brilliant" idea: put a logic analyzer on the IDE cable and measure the timings the prevailing OS family/BIOS uses? Sadly, I don't have access to a logic analyzer :( Anyone with (good) connections to a (university) hardware lab? /Marino > Ciao, > Sheldon. > > > To Unsubscribe: send mail to majordomo@FreeBSD.org > with "unsubscribe freebsd-current" in the body of the message To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message
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