Date:	Thu, 31 May 2007 00:56:56 +0200
From:	Bartlomiej Zolnierkiewicz <bzolnier@...il.com>
To:	"Daniel J Blueman" <daniel.blueman@...il.com>
Cc:	linux-ide@...r.kernel.org,
	"Linux Kernel" <linux-kernel@...r.kernel.org>,
	Jeff Garzik <jeff@...zik.org>,
	Alan Cox <alan@...rguk.ukuu.org.uk>
Subject: Re: Compact Flash performance...


Hi,

Since you are using libata ata_piix driver and not IDE piix one
Jeff and/or Alan are the right people to ask this question...

Anyway...

On Thursday 31 May 2007, Daniel J Blueman wrote:
> I have a SanDisk Extreme IV 4GB CF card, capable of 40MB/s read, but
> am seeing 30MB/s read [1], connected directly to the IDE bus on my
> ICH8 controller.
> 
> How can I find out if this would be a timing or configuration issue?
> On 2.6.20.5 [2], the 120nS timing looks to be right [3], but perhaps

multi-word DMA cycle timing seems to be configured OK

Shouldn't really matter since it is for multi-word DMA transfers
and this device is using UDMA transfers.

> no multi-word transfer is hurting here...alas, it can't be enabled
> with the libata subsystem and 'hdparm -m', so what else?

-m is for multi sector PIO transfers and probably won't help here

Everything (except harmless "abnormal status" garbage) seems fine.

Where does the max 40MB/s come from?  Were you able to get this device to
work with this speed using some other controller and/or other OS-es?

Thanks,
Bart

> Daniel
> 
> --- [1]
> 
> # hdparm -t /dev/sdb
> /dev/sdb:
>  Timing buffered disk reads:   94 MB in  3.05 seconds =  30.79 MB/sec
> 
> --- [2]
> 
> ata7: PATA max UDMA/100 cmd 0x000000000001bc00 ctl 0x000000000001b882
> bmdma 0x000000000001b400 irq 17
> ata7.00: CFA: SanDisk SDCFX-4096, HDX 4.04, max UDMA/66
> ata7.00: 8027712 sectors, multi 0: LBA
> ata7.00: configured for UDMA/66
> ATA: abnormal status 0x7F on port 0x000000000001b807
> scsi 6:0:0:0: Direct-Access     ATA      SanDisk SDCFX-40 HDX  PQ: 0 ANSI: 5
> SCSI device sdb: 8027712 512-byte hdwr sectors (4110 MB)
> sdb: Write Protect is off
> sdb: Mode Sense: 00 3a 00 00
> SCSI device sdb: write cache: disabled, read cache: enabled, doesn't
> support DPO or FUA
> SCSI device sdb: 8027712 512-byte hdwr sectors (4110 MB)
> sdb: sdb1
> sd 6:0:0:0: Attached scsi removable disk sdb
> 
> --- [3]
> 
> # hdparm -I /dev/sdb
> 
> /dev/sdb:
> 
> CompactFlash ATA device, with removable media
>         Model Number:       SanDisk SDCFX-4096
>         Serial Number:      116802D2807J3335
>         Firmware Revision:  HDX 4.04
> Standards:
>         Supported: 4
>         Likely used: 4
> Configuration:
>         Logical         max     current
>         cylinders       7964    7964
>         heads           16      16
>         sectors/track   63      63
>         --
>         CHS current addressable sectors:    8027712
>         LBA    user addressable sectors:    8027712
>         device size with M = 1024*1024:        3919 MBytes
>         device size with M = 1000*1000:        4110 MBytes (4 GB)
> Capabilities:
>         LBA, IORDY(may be)(cannot be disabled)
>         Standby timer values: spec'd by Vendor
>         R/W multiple sector transfer: Max = 4   Current = 0
>         DMA: mdma0 mdma1 mdma2 udma0 udma1 udma2 udma3 *udma4
>              Cycle time: min=120ns recommended=120ns
>         PIO: pio0 pio1 pio2 pio3 pio4
>              Cycle time: no flow control=120ns  IORDY flow control=120ns
> Commands/features:
>         Enabled Supported:
>                 Write cache
>            *    CFA feature set
> -- 
> Daniel J Blueman
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