sparc64/164226: Data corruption on 9.0-RELEASE when reading from CDROM

[Marius Strobl]

The following reply was made to PR sparc64/164226; it has been noted by GNATS.

From: Marius Strobl <marius at alchemy.franken.de>
To: Alexander Motin <mav at FreeBSD.org>
Cc: freebsd-gnats-submit at FreeBSD.org, "C. P. Ghost" <cpghost at cordula.ws>
Subject: Re: sparc64/164226: Data corruption on 9.0-RELEASE when reading from CDROM
Date: Sat, 21 Jan 2012 01:59:19 +0100

 On Fri, Jan 20, 2012 at 08:50:05PM +0100, Marius Strobl wrote:
 > On Fri, Jan 20, 2012 at 09:40:35PM +0200, Alexander Motin wrote:
 > > On 01/20/12 21:32, Marius Strobl wrote:
 > > >On Fri, Jan 20, 2012 at 08:13:38PM +0200, Alexander Motin wrote:
 > > >>On 20.01.2012 19:51, Marius Strobl wrote:
 > > >>>Alexander, could you please look into this?
 > > >>>Apparently, using cd(4) with ATA_CAM on sparc64 causes seemingly
 > > >>>random data corruption while using the same hardware with acd(4)
 > > >>>doesn't. Also cd(4) works just fine with SPI CD-ROMs. This affects
 > > >>>CD-ROMs connected to both AcerLabs M5229 and CMD 646.
 > > >>>Btw., apparently hw.ata.ata_dma and w.ata.atapi_dma no longer
 > > >>>work when using ATA_CAM as ata_getparam() isn't called in the
 > > >>>first place. On a quick glance hw.ata.ata_dma_check_80pin and
 > > >>>hw.ata.wc probably also are no longer available with ATA_CAM.
 > > >>>Is there an alternative to these tunables to achieve the same
 > > >>>when using ATA_CAM?
 > > >>
 > > >>hw.ata.ata_dma and hw.ata.atapi_dma are indeed no longer exist. But
 > > >>hint.ata.X.mode and hint.ata.X.devX.mode are working. In run tame it can
 > > >>be done via `camcontrol negotiate cd0 -U -M mode; camcontrol rescan X`,
 > > >>where X is a CAM bus number.
 > > >>
 > > >>hw.ata.ata_dma_check_80pin still exist, but CAM ATA transport is no
 > > >>longer look on whet device thinks about cable type. It is tricky in SATA
 > > >>world. Cable type is checked only from controller driver side now. Looks
 > > >>like none of mentioned controller drivers are doing it.
 > > >>
 > > >>hw.ata.wc was replaced by kern.cam.ada.write_cache and
 > > >>kern.cam.ada.X.write_cache.
 > > >>
 > > >>I would start experiments from limiting transfer speed manually.
 > > >
 > > >Hrm, limitting the mode to PIO avoids the data corruption with
 > > >ATA_CAM.
 > > 
 > > What's about limiting speed to UDMA33? Is it DMA problem or result of 
 > > dropped device side cable detection that could limit to UDMA33 before?
 > > 
 > 
 > Apparently it's some sort of DMA problem. UDMA2 is also the maximum
 > negotiated with acd(4). Limitting to UDMA1, UDMA0 or even WDMA0
 > makes no differnce to the problem.
 
 ... for the ALi M5229 rev. 0xc4 that is. The CMD 646 is limited to
 WDMA2 in the firstplace, a user also reported data corruption with
 these though.
  
 Marius