Date: Sat, 24 Jul 1999 13:20:02 -0700 (PDT) From: Nick Hibma <nick.hibma@jrc.it> To: freebsd-bugs@FreeBSD.org Subject: Re: kern/8875: Patch to allow DMA IDE with generic chipset + UDMA drives (fwd) Message-ID: <199907242020.NAA71668@freefall.freebsd.org>
index | next in thread | raw e-mail
The following reply was made to PR kern/8875; it has been noted by GNATS. From: Nick Hibma <nick.hibma@jrc.it> To: freebsd-gnats-submit@freebsd.org Cc: Subject: Re: kern/8875: Patch to allow DMA IDE with generic chipset + UDMA drives (fwd) Date: Sat, 24 Jul 1999 20:48:48 +0200 (MET DST) ---------- Forwarded message ---------- Date: Sun, 25 Jul 1999 04:36:49 +1000 From: Bruce Evans <bde@zeta.org.au> To: n_hibma@FreeBSD.ORG Subject: Re: kern/8875: Patch to allow DMA IDE with generic chipset + UDMA drives >Synopsis: Patch to allow DMA IDE with generic chipset + UDMA drives > >State-Changed-From-To: open->analyzed >State-Changed-By: n_hibma >State-Changed-When: Sat Jul 24 04:21:24 PDT 1999 >State-Changed-Why: >It looks like an additional feature that is no longer necessary. >If I remeber correcctly support for Ali and Sis has been added). An unifdefed version of it was committed in rev.1.23, but should not have been. It was a quick fix for the author's Ali motherboard or BIOS but it is obviously wrong in general since it bogotifies the comment preceding it (the point of the "generic" support is to assume that everything is already set up correctly; any hardware programming risks disturbing the setup). It broke generic support on at least one of grog's systems (SiS IIRC). rev.1.23 also added Ali support, so the patch in the PR was certainly unnecessary for Ali. The SiS breakage was fixed a little later by adding proper SiS support. The ata driver does the same things as the patch. It's not clear that it helps there. It may harm by reprogramming the drive from UDMA2 to WDMA2. I think something like this happens on one of my systems, but it doesn't harm throughput or overhead. I only have PIIX1, VIA2 and PIIX4 to test. Bruce To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-bugs" in the body of the messagehome | help
Want to link to this message? Use this
URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?199907242020.NAA71668>