From mboxrd@z Thu Jan 1 00:00:00 1970 From: Michael Schmitz Subject: Re: [PATCH 0/2] Experimental Amiga Zorro ESP driver Date: Mon, 19 Aug 2013 20:48:24 +1200 Message-ID: <5211DBD8.5090801@gmail.com> References: <1370552199-15048-1-git-send-email-schmitz@debian.org> <520D4AE3.6040801@aalto.fi> <520E76FC.9040803@aalto.fi> <11425cb5ec432e2fbb7b675052e8b33d@gmail.com> <520F5F81.7090409@aalto.fi> <52102BEC.7000006@gmail.com> <52108CAF.1010700@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from mail-pd0-f176.google.com ([209.85.192.176]:60984 "EHLO mail-pd0-f176.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751107Ab3HSIsj (ORCPT ); Mon, 19 Aug 2013 04:48:39 -0400 Received: by mail-pd0-f176.google.com with SMTP id q10so4852032pdj.21 for ; Mon, 19 Aug 2013 01:48:39 -0700 (PDT) In-Reply-To: Sender: linux-m68k-owner@vger.kernel.org List-Id: linux-m68k@vger.kernel.org To: Geert Uytterhoeven Cc: Tuomas Vainikka , Linux/m68k Geert, > On Sun, Aug 18, 2013 at 10:58 AM, Michael Schmitz wrote: > >> I'll also need to check the command_block and command_block_dma addresses - >> does the DMA require virtual or physical addresses? >> > > Physical, of course. > :-) VDMA was invented a bit later ... I'll go check the usage of the DMA API calls again, but as the driver seems to do DMA fine until the short transfer, that seems the most likely cause. PIO for dma_count < 7 might be an option. I see transfers with esp_count=1 and dma_count=7 in the log - wonder why that works but the short 2/2 byte case does not. Cheers, Michael