Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754093AbbKWWzX (ORCPT ); Mon, 23 Nov 2015 17:55:23 -0500 Received: from smtp-1b.atlantis.sk ([80.94.52.26]:60729 "EHLO smtp-1b.atlantis.sk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751166AbbKWWzU (ORCPT ); Mon, 23 Nov 2015 17:55:20 -0500 From: Ondrej Zary To: Finn Thain Subject: Re: [PATCH 00/71] More fixes, cleanup and modernization for NCR5380 drivers Date: Mon, 23 Nov 2015 23:55:03 +0100 User-Agent: KMail/1.9.10 (enterprise35 0.20100827.1168748) Cc: Sam Creasey , Michael Schmitz , "James E.J. Bottomley" , linux-m68k@vger.kernel.org, linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org References: <20151118083455.331768508@telegraphics.com.au> <201511211401.39957.linux@rainbow-software.org> In-Reply-To: X-KMail-QuotePrefix: > MIME-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <201511232355.04017.linux@rainbow-software.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3199 Lines: 67 On Sunday 22 November 2015 00:32:31 Finn Thain wrote: > > On Sat, 21 Nov 2015, Ondrej Zary wrote: > > > On Saturday 21 November 2015 02:58:57 Finn Thain wrote: > > > > > > > > I gather that your setup here is a QUANTUM LP240S target with Domex > > > 3181 (DTC-436) card and g_NCR5380 module. I've been testing a similar > > > setup: QUANTUM LPS540S target with a Domex 3191D (DTC-536) card and > > > dmx3191d module. In both setups PIO is used exclusively, no IRQ is > > > used, and FLAG_DTC3181E is set. I didn't see any issues in my tests, > > > so your results are surprising. > > > > I agree that the results are surprising. Even tried 2.4 kernels (Debian > > 3.1) and even 2.2 (Debian 3.0) and nothing worked. HW is fine - the > > drive is accessible in Windows 98 (with Domex driver installed). > > That's good to know (and very thorough). > > > > > Now testing the Canon FG2-5202 controller - a simple 8-bit ISA card with > > only two chips: NCR 53C400 and 74LS245. It's memory mapped, IRQ > > hardwired to 7. > > > > # modprobe g_NCR5380_mmio ncr_irq=255 ncr_addr=0xd8000 ncr_53c400=1 > > > > [ 1245.919223] scsi2 : interrupts not enabled. for better interactive performance, > > [ 1245.919326] scsi2 : please jumper the board for a free IRQ. > > [ 1245.919389] scsi host2: Generic NCR5380/NCR53C400 SCSI, io_port 0x0, n_io_port 0, base 0xd8000, irq 0, can_queue 16, cmd_per_lun 2, sg_tablesize 128, this_id 7, flags { NCR53C400 }, USLEEP_POLL 3, USLEEP_WAITLONG 1250, options { AUTOPROBE_IRQ PSEUDO_DMA NCR53C400 } > > [ 1246.376738] scsi 2:0:1:0: Direct-Access QUANTUM LP240S GM240S01X 4.6 PQ: 0 ANSI: 2 CCS > > [ 1248.202198] sd 2:0:1:0: Attached scsi generic sg1 type 0 > > [ 1248.420856] 53C400r: no 53C80 gated irq after transfer > > [ 1248.420948] 53C400r: no end dma signal > > [ 1248.422459] sd 2:0:1:0: [sdb] Sector size 0 reported, assuming 512. > > > > Seems that the PSEUDO_DMA is broken. > > That's been my experience with mac_scsi also (going back 10 years). I'm > told that it used to work in v2.2. PIO was always usable though hopelessly > slow. > > I haven't yet done any work on the PDMA problem with mac_scsi because > crashing bugs and the forked core driver seemed to be the more pressing > problems. And resolving the fork has implications for all of the DMA > variations anyway. PDMA seems to be broken in multiple ways. NCR5380_pread cannot process less than 128 bytes. In fact, 53C400 datasheet says that it's HW limitation: non-modulo-128-byte transfers should use PIO. Adding transfersize = round_down(transfersize, 128); to generic_NCR5380_dma_xfer_len() improves the situation a bit. After modprobe, some small reads (8, 4, 24 and 64 bytes) are done using PIO, then eight 512-byte reads using PDMA and then it fails on a 254-byte read. First 128 bytes are read using PDMA and the next PDMA operation hangs waiting forever for the host buffer to be ready. -- Ondrej Zary -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/