Date: Sun, 26 Aug 2001 21:17:49 +0200 (CEST) From: Søren Schmidt <sos@freebsd.dk> To: Zhihui Zhang <zzhang@cs.binghamton.edu> Cc: freebsd-hackers@FreeBSD.ORG Subject: Re: ata0-master: non aligned DMA transfer attempted Message-ID: <200108261917.f7QJHnT68379@freebsd.dk> In-Reply-To: <Pine.SOL.4.21.0108261415301.9351-100000@opal> "from Zhihui Zhang at Aug 26, 2001 02:16:12 pm"
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It seems Zhihui Zhang wrote: > > Thanks for your replay. I use gdb to find out that the buffer address is > not 16-byte aligned. This leads to a question as to how to align a > statically allocated data structure properly. Using union seems to be able > to align you on a long boundary (or even long long?), but that is not 16 > byte aligned. For all ATA controllers except for one crappy exception, the buffer should just be on a 2byte aligned adresss, so using 16 or even 64 bytes as Julian suggested is not needed. But you can ONLY transfer 512bytes at a time. -Søren To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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