Date: Wed, 27 Jul 2011 09:55:20 -0700 From: Jeremy Chadwick <freebsd@jdc.parodius.com> To: Jan Mikkelsen <janm@transactionware.com> Cc: Tom Evans <tevans.uk@googlemail.com>, freebsd-stable@freebsd.org Subject: Re: SATA 6g 4-port non-RAID controller ? Message-ID: <20110727165520.GA15633@icarus.home.lan> In-Reply-To: <A5E8942B-A83B-46F9-900E-E74808B009E8@transactionware.com> References: <20110725093432.GI1202@home.opsec.eu> <CAOjFWZ6pbSeQ9hn4A-bf0Cy0fOTcyscCRyv61zxpSWFbMoHugw@mail.gmail.com> <20110726225557.GA97184@icarus.home.lan> <CAFHbX1JPJBzH6k2B==hKyS%2BpKOCCG_wFiGxePm3GfYo=vPj_GA@mail.gmail.com> <20110727101234.GA7659@icarus.home.lan> <A5E8942B-A83B-46F9-900E-E74808B009E8@transactionware.com>
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On Thu, Jul 28, 2011 at 02:31:20AM +1000, Jan Mikkelsen wrote: > On 27/07/2011, at 8:12 PM, Jeremy Chadwick wrote: > > > On Wed, Jul 27, 2011 at 10:38:36AM +0100, Tom Evans wrote: > >> On Tue, Jul 26, 2011 at 11:55 PM, Jeremy Chadwick > >> <freebsd@jdc.parodius.com> wrote: > >>> > >>> And before someone asks: in most cases you *cannot* use this card in a > >>> PCIe x16 connector on a motherboard. ??Most generic motherboard > >>> manufacturers at this point have special one-offs that assume their PCIe > >>> x16 slots are for video cards only. ??If you aren't sure, you'll need to > >>> ask your motherboard manufacturer/vendor if you can use a > >>> non-VGA-adapter in their PCIe x16 slot. ??Some Supermicro boards do have > >>> PCIe x16 slots that can be used by non-VGA adapters, but I haven't seen > >>> this on, say, Asus/Gigabyte/Dell/Intel motherboards. > >> > >> Jeremy may not have seen PCI express x16 HBAs working on consumer > >> boards, but I have, plenty of times. > > > > I'm glad -- people should probably start making a list, because the > > number of boards I've seen it not work in easily exceeds that of the > > times I HAVE seen it work. :-) > > Where did it fail? Nothing visible from the BIOS; not talking about POST, I'm talking about after power-on the system would spin up its fans and sit there. > >> I don't know why the FUD, but I have had no problems with an Intel > >> SASUC8I (LSI 1068 based) running on an Asus P5Q Pro, a simple consumer > >> P45 chipset. I'm not unique, many people have success doing this. > > > > Once in a blue moon, an intelligent board manufacturer puts comments in > > their user manual to the effect of "the PCIe x16 slot is only to be used > > for VGA adapters and will not work with non-VGA cards", or vice-versa. > > Here's some hard evidence of my claim: > > > > Supermicro X7SBA server-class motherboard user manual has the following > > line in it: > > > > "Note: The Intel 3210 chipset does not support add-in graphics cards in > > the PCI-E interface provided by the Memory Controller Hub (MCH)." > > > > So in that boards' case, the PCIe x16 slot (which only has PCIe x8 worth > > of lanes wired) will work with controller cards but not VGA adapters. > > > > And here's another, for the X7DVL series boards: > > http://www.supermicro.com/support/faqs/faq.cfm?faq=10582 > > > > "This is a server board, and you cannot place a x8 or x16 VGA card on > > this board. Only onboard VGA is possible. If you need to place a VGA > > card please use X7DA(x) board". > > Perhaps I'm being thick, but this says "a 16x slot on this board does not support a display card" not "a 16x slot on this board only supports a display card." > > The examples you cite only support the "vice-versa" part of your claim, not the primary claim that 16x slots on some motherboards are only for display cards. Do you have a reference for that? You're not being thick. I'm simply using what's in the manual as a hard, validated example that the *type* of card that goes into a PCIe x16 slot can matter, and that some types are compatible while others are not. I cannot find you a hard documented reference for my claims right now, so you can consider them lies/FUD/whatever for the time being, that's fine by me at this point. I can find you examples on Google of people who invested in Areca ARC-1220 cards (PCIe x8) only to find out that when inserted into one of their two PCIe x16 slots the mainboard wouldn't start (see above). I can also find you examples on Google of people with Intel 915GM chipsets whose user manuals explicitly state the PCIe x16 slot on their board is "intended for use with graphics cards only". > > And up until last week I owned and used an Asus P5Q SE (P45-based with > > ICH10 SB) board, so I can refer you to the fact that the P5Q Pro user > > manual "hints" that the PCIe x16 slot is for graphics only but doesn't > > downright say that. > > Did you try a non-graphics card in the slot to see what happened? Saying "The 16x slot is where you put the graphics card" is probably not unreasonable for 99% of the users of that board. No I did not. Let's recap my point because this will be my last reply on the matter: If your motherboard only has PCIe x16 slot(s) available in it, and the user manual doesn't say anything about the slot(s) being usable for non-graphics purposes, BEFORE shoving a non-VGA card in the slot, be sure to consult your user manual and the motherboard vendor to ensure the card will work. The assumption within the industry appears to be that PCIe x16 is "intended for VGA adapters", even though on an engineering level we all know there's no reason (other than design limitations of the board or chipsets) that non-VGA adapters can't be used. I can't explain to you how or why this limitation would come into play, but it obviously can, as the Supermicro board examples I provided are hard evidence of some boards and configurations discriminating based on what type of card goes into the slot. -- | Jeremy Chadwick jdc at parodius.com | | Parodius Networking http://www.parodius.com/ | | UNIX Systems Administrator Mountain View, CA, US | | Making life hard for others since 1977. PGP 4BD6C0CB |
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