Re: Kernel 2.6.37 erroneously limiting to UDMA/33

[Stephen Clark <sclark46@earthlink.net>]

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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