Re: UDMA with CS5530 using IBM Netvista N2200 (8363)

[Sergei Shtylyov <sshtylyov@ru.mvista.com>]

Hello.

Antonio Martins wrote:

>>>Booting with CONFIG_BLK_DEV_CS5530=n and CONFIG_PATA_CS5530=y and
>>>libdata_dma_mask=0
>>>kernel 2.6.24.7:
>>>...
>>>ide: Assuming 33MHz system bus speed for PIO modes; override with idebus=xx
>>>Driver 'sd' needs updating - please use bus_type methods
>>>scsi0: pata_cs5530
>>>scsi1: pata_cs5530
>>>ata1: PATA max UDMA/33 cmd 0x1f0 ctl 0x3f6 bmdma 0xfc00 irq 14
>>>ata2: PATA max UDMA/33 cmd 0x170 ctl 0x376 bmdma 0xfc08 irq 15
>>>ata1.00: ATA-5: SILICON POWER, 2.0, mas UDMA/66
>>>ata1.00: 2000880 sectors, multi 1: LBA
>>>ata1.00: configured for PIO4
>>>scsi 0:0:0:0: Direct-Access      ATA     SILICON POWER    2.0  PQ: 0 ANSI: 5
>>>sd 0:0:0:0: [sda] 2000880 512-byte hardware sectors (1024 MB)
>>>sd 0:0:0:0: [sda] Write Protect is off
>>>sd 0:0:0:0: [sda] Write cache: disabled, read cache: enabled, doesn't support DPO or FUA
>>>sd 0:0:0:0: [sda] 2000880 512-byte hardware sectors (1024 MB)
>>>sd 0:0:0:0: [sda] Write Protect is off
>>>sd 0:0:0:0: [sda] Write cache: disabled, read cache: enabled, doesn't support DPO or FUA
>>> sda: sda1

>>And now it all works nicely

>>>Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(0,0)
>>>So PIO4 is now working. Great. But i am stuck with the root device.

>>I would suggest posting to linux-kernel on that and talking to H Peter
>>Anvin about possible ways to get a real boot loader on the box.

> So regarding DMA, Netvista 8363 has this limitation, and there is no
> DMA or UDMA mode that we can successfully enable. The only way to
> force PIO4, is changing directly in the source code.
> If kernel parameters were supported, we would be able to use some "idebus"
> parameter. Are these statements correct?

    There's "libata.dma=" option (if you can pass it), set it to 0
and DMA won't ever be used.
    Note that the "old" IDE code also has the parameter controlling
DMA usage (even per drive) -- look for "nodma" in Documentation/ide/ide.txt.

MBR, Sergei