ad0 READ_DMA TIMEOUT errors on install of 7.0-RELEASE

[Jeremy Chadwick]

On Wed, Mar 26, 2008 at 07:19:47AM +0100, Gianni wrote:
> On 25/mar/08, at 09:44, Jeremy Chadwick wrote:
>>
>> I re-read your mail -- sorry.  You're using SATA.
>>
>> I'll update my Wiki page to state that the loader.conf DMA disable trick
>> only works for PATA.
>>
>> In the interim, I recommend you contact Scott Long, especially if your
>> problem is easily repeatable.  He's offered to help track this down.
>
> Thanks I'll try contacting Scott.
>
> In the meantime I think I have narrowed down the problem in my case to the 
> on-board Promise SATA controller.
> My motherboard has 2 SATA controllers, one Promise and one Via and I have 2 
> sets of disks with gmirror RAID 1 - 2xSeagate Barracuda + 2xWD5000YS.
> atapci0: <Promise PDC20378 SATA150 controller>
> atapci1: <VIA 6420 SATA150 controller>
>
> The Western Digital disks were connected to the Promise controller and 
> giving the READ_DMA TIMEOUT errors, I've now swapped the disks around so 
> the Seagate ones are attached to the Promise controller and now these are 
> reporting the errors.
> So it seems I can definitely exclude disk hardware problems.

Another possibility is cables.  There have been a couple reports in the
past of people receiving said errors and swapping cables has completely
ridded them of the problem.

If you swap cables and the problem continues, then this is definitely
something within the FreeBSD ATA layer, or something very close to it.

FreeBSD has excellent Promise controller support, since Promise provides
Soren with all the necessary technical documents of how to interface
with their controllers.  So, I don't think the controller is the problem
(because of so many reports of this issue on non-Promise controllers,
ranging from VIA to Intel to nVidia to ATI), nor do I think your disks
are the issue.

You would be a very good test subject (sorry to phrase it like that) for
Scott.  :-)

-- 
| Jeremy Chadwick                                    jdc at parodius.com |
| Parodius Networking                           http://www.parodius.com/ |
| UNIX Systems Administrator                      Mountain View, CA, USA |
| Making life hard for others since 1977.                  PGP: 4BD6C0CB |