Re: Kernel 2.6.37 erroneously limiting to UDMA/33

[Stephen Clark]

On 01/05/2011 06:50 PM, Robert Hancock wrote:
> (CCing linux-ide)
>
> On 01/05/2011 12:33 PM, Stephen Clark wrote:
> > Hello,
> >
> > Why is the kernel limiting me to udma/33 when the device says it can do
> > ata2.01: CFA: TRANSCEND, 20070831, max UDMA/66
> >
> > There is no cable the compact flash is a socket on the motherboard!
>
> The kernel has no way to know that, and presumably the board isn't 
> connecting the signal for IDE pin 34 to ground in order to properly 
> signal that an 80-wire cable (or equivalent) is connected so that 
> speeds over UDMA33 can be used.
>
> You should be able to use the libata.force=80c option on the kernel 
> command line to override the cable detection.
>
> > Loading sd_mod.ko module
> > Loading libata.ko module
> > Loading ata_generic.ko module
> > Loading pata_acpi.ko module
> > pata_acpi 0000:00:0f.0: PCI INT B -> GSI 21 (level, low) -> IRQ 21
> > pata_acpi 0000:00:0f.0: PCI INT B disabled
> > Loading pata_via.ko module
> > scsi0 : pata_via
> > scsi1 : pata_via
> > ata1: PATA max UDMA/133 cmd 0x1f0 ctl 0x3f6 bmdma 0xfa00 irq 14
> > ata2: PATA max UDMA/133 cmd 0x170 ctl 0x376 bmdma 0xfa08 irq 15
> > ata2.01: CFA: TRANSCEND, 20070831, max UDMA/66
> > ata2.01: 7962192 sectors, multi 0: LBA
> > ata2.01: limited to UDMA/33 due to 40-wire cable
> > ata2.01: configured for UDMA/33
> > scsi 1:0:1:0: Direct-Access ATA TRANSCEND 2007 PQ: 0 ANSI: 5
> > sd 1:0:1:0: [sda] 7962192 512-byte logical blocks: (4.07 GB/3.79 GiB)
> > sd 1:0:1:0: [sda] Write Protect is off
> > sd 1:0:1:0: [sda] Write cache: disabled, read cache: enabled, doesn't
> > support DA
> > sda: sda1 sda2 sda3
> > sd 1:0:1:0: [sda] Attached SCSI disk
> > Loading ata_piix.ko module
> >
> > Thanks,
> > Steve

Hmm... libata.force=80c - didn't seem to work.

  Booting command-list

root (hd0,0)
 Filesystem type is ext2fs, partition type 0x83
kernel /vmlinuz-2.6.37 ro root=LABEL=/ console=ttyS0,115200n8 
libata.force=80c
   [Linux-bzImage, setup=0x3c00, size=0x2ad060]
initrd /initrd-2.6.37.img
   [Linux-initrd @ 0x1fd59000, 0x286776 bytes]
...
Loading pata_via.ko module
scsi0 : pata_via
scsi1 : pata_via
ata1: PATA max UDMA/133 cmd 0x1f0 ctl 0x3f6 bmdma 0xfa00 irq 14
ata2: PATA max UDMA/133 cmd 0x170 ctl 0x376 bmdma 0xfa08 irq 15
ata2.01: CFA: TRANSCEND, 20070831, max UDMA/66
ata2.01: 7962192 sectors, multi 0: LBA
ata2.01: limited to UDMA/33 due to 40-wire cable
ata2.01: configured for UDMA/33
scsi 1:0:1:0: Direct-Access     ATA      TRANSCEND        2007 PQ: 0 ANSI: 5
sd 1:0:1:0: [sda] 7962192 512-byte logical blocks: (4.07 GB/3.79 GiB)
sd 1:0:1:0: [sda] Write Protect is off
sd 1:0:1:0: [sda] Write cache: disabled, read cache: enabled, doesn't 
support DA
 sda: sda1 sda2 sda3
sd 1:0:1:0: [sda] Attached SCSI disk

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deserve neither liberty nor safety."  (Ben Franklin)

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