Date: Sun, 22 Mar 2009 19:43:44 -0500 (CDT) From: Nathan Whitehorn <nwhitehorn@freebsd.org> To: Justin Hibbits <jrh29@alumni.cwru.edu> Cc: freebsd-ppc@freebsd.org Subject: Re: Apple ATA DMA problems with ATAPI Message-ID: <alpine.BSF.2.00.0903221941130.18715@banshee.munuc.org> In-Reply-To: <20090322215406.GA1257@narn.knownspace> References: <20090322180638.GA3708@narn.knownspace> <8B9483E9-D6D4-441E-9202-31FA34F5DA98@mac.com> <20090322215406.GA1257@narn.knownspace>
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On Sun, 22 Mar 2009, Justin Hibbits wrote: > On Sun, Mar 22, 2009 at 01:41:18PM -0700, Marcel Moolenaar wrote: >> >> On Mar 22, 2009, at 11:06 AM, Justin Hibbits wrote: >> >>> Well, it seems I was bitten by the ATA DMA problems from a few >>> months back. >> >> Try disabling DMA for atapi in /boot/loader.conf and enable >> it in /etc/sysctl.conf. For some reason, on my Mac Mini at >> least, it helps to first program PIO and then program *DMA. >> >> YMMV, >> >> -- >> Marcel Moolenaar >> xcllnt@mac.com >> >> >> > > It appears hw.ata.atapi_dma is a read-only tunable, so /etc/sysctl.conf has no > effect on it, and only throws a warning about being unable to change it. It's > working sufficiently as PIO, though. > So it looks like this issue is limited to ATAPI devices, and as a result I have one more stab in the dark. Apparently at least some of these controllers die if you try to give them an ATAPI command with a length that is not divisible by 16. I have a patch at http://people.freebsd.org/~nwhitehorn/ata-alignment.diff that converts such commands to PIO. Could you see if it works? If this fails, I'll apply a sledgehammer and force all ATAPI devices on Apple controllers to PIO. -Nathan
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