From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <3DD25896.6020603@uab.ericsson.se> Date: Wed, 13 Nov 2002 14:50:14 +0100 From: Hans Feldt MIME-Version: 1.0 To: Joakim Tjernlund Cc: linuxppc-embedded@lists.linuxppc.org, scop@digitel.com.br, thomas@corelatus.com Subject: Re: [PATCH] arch/ppc/8xx_io/enet.c, version 2 References: <200210241423.g9OENV4d024137@blooper.utfors.se> Content-Type: text/plain; charset=us-ascii; format=flowed Sender: owner-linuxppc-embedded@lists.linuxppc.org List-Id: On 10/24/02 04:23 PM, Joakim Tjernlund wrote: > Hi > > This is the second version of my patch that removes the expensive memcpy of > received > ethernet frames in interrupt context. Isn't it so that this patch works because you have snooping? Without snooping the driver would fail because of cache line replacement which could trash received data. The buffer invalidate in this case is unneeded. But if you wanna optimise you should invalidate the whole buffer before giving it to DMA thus getting rid of the flush implied by memory coherence. Tried this out in a driver for a processor without snooping, now and then received packets got corrupted, cache line wise... Just trying to understand how things really work, please correct me if I am wrong. Cheers, Hans ** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/