--- Tejun Heo <htejun@xxxxxxxxx> wrote:
> Hello,
Hello,
> Srihari Vijayaraghavan wrote:
> > --- Tejun Heo <htejun@xxxxxxxxx> wrote:
> >> It just seems sb600 claims that it can do DMA above 4G while it actually
> >> can't. Can you test the attached patch?
[...]
> > With your patch, with 4 GB of RAM, all SATA drives are detected & working
> > normally. For the record dmesg is attached.
>
> Thanks for testing.
Thank you for providing a good patch.
[...]
> Oh well, that's the price you have to pay when you 1. have a device
> which can't access memory above 4G but 2. don't have IOMMU to do it for
> the device. If performance becomes problem, you can always get a
> not-so-expensive external controller which can do 64.
Well, I think my AM2 chip is capable of IOMMU (well that's one of the deciding
factor even since my original AMD64 3200+ :-)). BTW is there an easier way to
prove whether IOMMU is in use?
> Yeap, I'll forward it upstream and probably to -stable too. The problem
> here is that I'm not sure whether the problem is in the ahci controller
> itself or some bridge chip above it.
Fair enough.
> It would be best if Conke Hu can
> verify this but you can also test it by buying a ATA controller which
> can do 64bit and whether it works properly on the machine. :-)
Let's hope he does.
Buying an (S)ATA controller now is a lofty goal (for the lack of money more
than anything :-)). But doesn't my current on-board IDE doesn't do 64bit DMA?
Here is its lspci -vvv:
00:14.1 IDE interface: ATI Technologies Inc SB600 IDE (prog-if 82 [Master
PriP])
Subsystem: ASUSTeK Computer Inc. Unknown device 81ef
Control: I/O+ Mem- BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr-
Step
ping- SERR- FastB2B-
Status: Cap+ 66MHz+ UDF- FastB2B- ParErr- DEVSEL=medium >TAbort-
<TAbort
- <MAbort- >SERR- <PERR-
Latency: 64
Interrupt: pin A routed to IRQ 16
Region 0: I/O ports at 01f0 [size=8]
Region 1: I/O ports at 03f4 [size=1]
Region 2: I/O ports at 0170 [size=8]
Region 3: I/O ports at 0374 [size=1]
Region 4: I/O ports at f900 [size=16]
Capabilities: [70] Message Signalled Interrupts: Mask- 64bit-
Queue=0/0
Enable-
Address: 00000000 Data: 0000
I'm not sure if this IDE controller is operating in 64 bit DMA?? (well if it
didn't my IDE peripherals might not have worked properly without mem=4095M,
like the SATA controller, no? They always worked fine.) I thought all PCI-E
based devices were capable, no?
Thanks
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