From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tuomas Vainikka Subject: Re: [PATCH 0/2] Experimental Amiga Zorro ESP driver Date: Mon, 19 Aug 2013 14:47:15 +0300 Message-ID: <521205C3.1060807@aalto.fi> 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> <5211DBD8.5090801@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from mx04.aalto.fi ([130.233.222.103]:55517 "EHLO mx04.aalto.fi" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751286Ab3HSLrR (ORCPT ); Mon, 19 Aug 2013 07:47:17 -0400 In-Reply-To: <5211DBD8.5090801@gmail.com> Sender: linux-m68k-owner@vger.kernel.org List-Id: linux-m68k@vger.kernel.org To: Michael Schmitz Cc: Geert Uytterhoeven , Linux/m68k On 08/19/2013 11:48 AM, Michael Schmitz wrote: > 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. > Is it possible that the problem is with memory alignment? http://fxr.watson.org/fxr/source/arch/amiga/dev/bzivsc.c?v=NETBSD#L360 https://groups.google.com/d/msg/comp.sys.amiga.hardware/FXwaSFoAPxc/zsXeP7PB6RoJ -Tuomas