Date: Tue, 12 Feb 2002 01:02:35 +0100 (CET) From: =?ISO-8859-1?Q?G=E9rard_Roudier?= <groudier@free.fr> To: Joerg Wunsch <joerg_wunsch@uriah.heep.sax.de> Cc: <freebsd-scsi@FreeBSD.ORG> Subject: Re: SCSI parity error detected Message-ID: <20020212004513.X2315-100000@gerard> In-Reply-To: <200202121933.g1CJXCF87301@uriah.heep.sax.de>
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On Tue, 12 Feb 2002, Joerg Wunsch wrote: > G=E9rard Roudier <groudier@free.fr> wrote: > > >> This Dawicontrol is 8-bit only btw., despite of using an 53c875. > > > But the driver cannot guess it. And it doesn't understand the > > Dawicontrol settings from NVRAM (if some exists). > > But don't we have a problem here then? May-be. If you can get the NVRAM layout and some data sheet about a possible NVRAM type, let me know. ;) Btw, if Dawicontrol uses PCI sub-vendor ids or some GPIO specific wiring to identify their controller, I can let the driver probe such kind of stuff. But unfortunately, I have exactly no info about those controllers. > The controller uses a chip that could do 16 bit, but has only an 8-bit > bus attached. Since there's no NVRAM on it, there's no chance for the > driver to tell this. As soon as another 16-bit capable device > appears, this device would also try to negotiate 16-bit when asked for > (since it doesn't know about the 8-bitness of its bus adapter), and > there's no chance for user intervention to tell the controller to > restrict everything to 8 bit. Btw, under Linux, this can be achieved using boot command parameters. Under FreeBSD, such facility didn't exist at the time I worked on that. Note that this can be achieved from the kernel config file using appropriate SYM_* defines and building a custom driver. (user can look into sym_conf.h file. There are tons of options) > > OTOH, if there is no such message in the log, it could well be the > > initial INQUIRY response that got a SCSI PARITY error. The problem > > might then be the/a SCSI PARITY signal not being properly > > driven/connected. > > What happens if the upper 8 bit are just terminated only on the > controller? Would this generate a parity error? There is no risk as long as no device accepts a Wide Negotiation. If one does, boom!! > Sure, that controller looks fairly crappy by design to me (Frank > meanwhile replaced it by a better one), but since we claim we > support the entire Symbios Logic line, we IMHO should offer a > method to fallback to safe defaults. (For -current, could perhaps > be done in the device hints, but that'd cause a chicken-and-egg > problem when installing.) The crappyness is to use undocumented stuff, in my opinion. Will look into device hints again. Last time I did, this didn't fit. The safe default it to use hardware correctly. A SCA adapter that shrinks 16 bits BUS to 8 bit BUS, device being connected on the 16 bit side and a Wide controller castrated to 8 bit connected to the 8 bit is an horror that fails as expected. G=E9rard. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-scsi" in the body of the message
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