From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:57165) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZLbvz-0001di-U1 for qemu-devel@nongnu.org; Sat, 01 Aug 2015 14:55:05 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ZLbvv-0000N9-AF for qemu-devel@nongnu.org; Sat, 01 Aug 2015 14:55:03 -0400 Received: from s16892447.onlinehome-server.info ([82.165.15.123]:52658) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZLbvv-0000Mo-3p for qemu-devel@nongnu.org; Sat, 01 Aug 2015 14:54:59 -0400 Message-ID: <55BD15F7.5090400@ilande.co.uk> Date: Sat, 01 Aug 2015 19:54:47 +0100 From: Mark Cave-Ayland MIME-Version: 1.0 References: <1438448070-32552-1-git-send-email-mark.cave-ayland@ilande.co.uk> <20150801183337.GA10456@aurel32.net> In-Reply-To: <20150801183337.GA10456@aurel32.net> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCHv2] macio: handle non-block ATAPI DMA transfers the same as block DMA transfers List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Aurelien Jarno Cc: jsnow@redhat.com, agraf@suse.de, qemu-devel@nongnu.org On 01/08/15 19:33, Aurelien Jarno wrote: > On 2015-08-01 17:54, Mark Cave-Ayland wrote: >> The existing code incorrectly changes the dma_active flag when a non-block >> transfer has completed leading to a hang on newer versions of Linux because the >> IDE and DMA engines deadlock waiting for each other. >> >> Instead copy the buffer directly to RAM, set the remaining transfer size to 0 and >> then invoke the ATAPI callback manually once again to correctly finish the >> transfer in an identical manner to a block transfer. >> >> Signed-off-by: Mark Cave-Ayland >> --- > > Thanks for the patch, it improves things here. I don't get messages > anymore, and I get less messages when mounting the CD-ROM, though I > still get one: > > [ 307.258463] pata-macio 0.00021000:ata-4: timeout flushing DMA > [ 307.262856] ata2.00: exception Emask 0x0 SAct 0x0 SErr 0x0 action 0x0 > [ 307.262919] ata2.00: BMDMA stat 0x6 > [ 307.263048] sr 1:0:0:0: CDB: Get configuration: 46 00 00 28 00 00 00 00 10 00 > [ 307.263289] ata2.00: cmd a0/01:00:00:10:00/00:00:00:00:00/a0 tag 0 dma 16400 in > [ 307.263297] res 41/50:03:00:10:00/00:00:00:00:00/a0 Emask 0x20 (host bus error) > [ 307.263407] ata2.00: status: { DRDY ERR } > [ 307.271251] ata2.00: configured for MWDMA2 > [ 307.271824] ata2: EH complete > > The CD-ROM is fully functional though. Hmmmm yes I can recreate that here - must be another transition between the non-block and the block transfer code (I was working on eliminating the boot messages) caused by reading the disc metadata upon mount. Unfortunately I don't have much time to work on this right now so maybe it's a 2.4.1/2.5 thing unless John can take a look? ATB, Mark.