Date: Thu, 7 Feb 2002 20:00:24 +0100 (CET) From: =?ISO-8859-1?Q?G=E9rard_Roudier?= <groudier@free.fr> To: Josef Karthauser <joe@tao.org.uk> Cc: Terry Lambert <tlambert2@mindspring.com>, "Eugene M. Kim" <gene@nttmcl.com>, Oliver Fromme <olli@secnetix.de>, FreeBSD Hardware Mailing List <hardware@FreeBSD.ORG>, FreeBSD Hackers Mailing List <hackers@FreeBSD.ORG> Subject: Re: USB "Memorybird" quirks Message-ID: <20020207193911.U1513-100000@gerard> In-Reply-To: <20020207235746.E46984@genius.tao.org.uk>
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On Thu, 7 Feb 2002, Josef Karthauser wrote: > On Thu, Feb 07, 2002 at 03:52:26PM -0800, Terry Lambert wrote: > > > > > > IIRC this problem is being addressed at a more fundamental level on > > > -current, by adding a 6-byte-to-10-byte READ command translator > > > somewhere in the abstraction layer. > > > > Could this be "auto-quirked"? > > > > As in, try a 6 byte command, and if that fails try a 10 byte command > instead? > > Unfortunately although I'm maintaining USB in -current, I don't have a > complete in depth understanding of the code yet. :( I'm mainly trying > to fix my problems by taking from NetBSD. A couple of READ/WRITE 6 byte commands are still mandatory for SCSI block devices in order to accomodate softwares as boot software for example that may not be upgradable on systems still in use. Softwares that are maintained should no longer use 6 byte commands, but use the 10 byte commands replacement (for years...). So, unless we want to accomodate applications that still may send 6 byte commands through passthrough driver, no translator should be needed. Just make class drivers use 10 byte commands instead. I donnot know about USB in details. But since USB is a recent technology USB devices should not be required to support READ/WRITE 6 byte commands. OTOH, using 6 byte READ/WRITE commands is very restrictive if we ever want to implemement kind of trustable disk write caching support since they do not allow to selectively force media access (this is achieved by the FUA bit in >=3D 10 byte READ/WRITE command). As a result, no device should be quirked nowadays as failing READ/WRITE 6 byte commands. Just maintained softwares should get rid of those commands asap. G=E9rard. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hardware" in the body of the message
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