From mboxrd@z Thu Jan 1 00:00:00 1970 Message-Id: <5.1.0.14.2.20030925134712.03b0ef78@mail.ebshome.net> Date: Thu, 25 Sep 2003 13:54:23 -0700 To: Roland Dreier From: Eugene Surovegin Subject: Re: Any restrictions on DMA address boundry? Cc: Bret Indrelee , Matt Porter , Linux PPC Embedded mailing list In-Reply-To: <52k77wk9mj.fsf@topspin.com> References: Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; format=flowed Sender: owner-linuxppc-embedded@lists.linuxppc.org List-Id: At 11:26 AM 9/25/2003, Roland Dreier wrote: >People often come up with complicated schemes like flushing and >invalidating the cache before and after the DMA transfer, but there's >always a scenario where the DMA buffer and/or the unrelated data get >corrupted. The only solution is to make sure that you don't put >unrelated data in the same cache line as a DMA buffer. Well, I'm one of those strange people. Actually, those schemes are quite trivial and they help in _real_ life. I fully understand that they are not 100% foolproof, but I think they are _better_ than doing _nothing_. I already _wasted_ a lot of my time debugging cache coherency problems. I cannot audit _all_ drivers/subsystems I use nor I can force their authors do this. Eugene. ** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/