From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:53536) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YvrYt-0002mx-AO for qemu-devel@nongnu.org; Fri, 22 May 2015 14:20:52 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1YvrYo-0004kA-Oh for qemu-devel@nongnu.org; Fri, 22 May 2015 14:20:47 -0400 Message-ID: <555F7367.5080103@redhat.com> Date: Fri, 22 May 2015 14:20:23 -0400 From: John Snow MIME-Version: 1.0 References: <1425939893-14404-1-git-send-email-mark.cave-ayland@ilande.co.uk> <555F6D89.4090309@redhat.com> <555F727A.2030404@ilande.co.uk> In-Reply-To: <555F727A.2030404@ilande.co.uk> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [RFC 0/2] macio: split out unaligned DMA access into separate functions List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Mark Cave-Ayland , qemu-devel@nongnu.org, qemu-ppc@nongnu.org, kwolf@redhat.com, stefanha@redhat.com, agraf@suse.de On 05/22/2015 02:16 PM, Mark Cave-Ayland wrote: > On 22/05/15 18:55, John Snow wrote: > >> On 03/09/2015 06:24 PM, Mark Cave-Ayland wrote: >>> This patchset attempts to separate out the IDE/ATAPI logic from the unaligned >>> DMA access logic for macio which provides the following benefits: >>> >>> 1) Reduced code complexity >>> >>> The existing macio IDE/ATAPI functions were becoming extremely difficult to >>> follow through the various callbacks. By splitting up the functions in this >>> way it becomes much easier to follow the DMA-specific sections of code. >>> >>> 2) Future-proofing >>> >>> If/when the block layer becomes able to handle unaligned DMA accesses directly >>> then it should be possible to switch out pmac_dma_read() and pmac_dma_write() >>> with their unaligned-capable bdrv_*() equivalents without having to change any >>> other logic. >>> >>> 3) Fix intermittent CDROM detection under -M g3beige >>> >>> The code refactoring now correctly handles non-block ATAPI transfers which >>> fixes the problem with intermittent CDROM detection with Darwin under >>> -M g3beige. >>> >>> Signed-off-by: Mark Cave-Ayland >>> >>> >>> Mark Cave-Ayland (2): >>> macio: move unaligned DMA read code into separate pmac_dma_read() >>> function >>> macio: move unaligned DMA write code into separate pmac_dma_write() >>> function >>> >>> hw/ide/macio.c | 487 +++++++++++++++++++++++--------------------- >>> include/hw/ppc/mac_dbdma.h | 4 - >>> 2 files changed, 254 insertions(+), 237 deletions(-) >>> >> >> Code fails 32 bit build due to %lx debug prints. I'll edit them >> accordingly if that is OK by you. > > Please go right ahead :) Do you need a proper re-spin without the RFC > prefix? If so, I can make the changes there if that helps? > > > ATB, > > Mark. > Nah, the tags seem to get dropped when you pull everything into git anyway, so it's no biggie. Thanks, --js As a post-script, can Darwin/PPC use a different mechanism for ATA at all, or is macio the sole ATA interface we support here? I want to see if I can pinpoint when a "good" bath and when a bad path diverges with respect to the disk contents ... Or if you have other ideas on how to identify the transfer that causes the issue, I'm all ears.