Re: [PATCH 02/15] ATA : vortex86 : fix vortex86dx/sx hardware CRC bug.

[Paul Schilling]

Hi,

When I developed this patch for the Vortex86dx.  I recall trying many
combinations of udma and mwdma.  At the time I developed it, I came
to the conclusion that both udma and mwdma both failed with CRC
errors being reported.  I am not readily set-up to redo the testing to
see if mwdma is indeed also affected by the errata.  It will be a couple
of weeks before I can re-test this patch on the hardware with mwdma
turned on.

Thanks,
Paul

On Thu, Oct 27, 2011 at 2:43 AM, Alan Cox <alan@xxxxxxxxxxxxxxxxxxx> wrote:
> On Tue, 25 Oct 2011 23:16:04 -0500
> Paul Schilling <paul.s.schilling@xxxxxxxxx> wrote:
>
>> This fixes a DMA issue related to a CRC bug on
>> the RDC pata peripherial found on the vortex86sx and vortex86dx.
>
> What is the RDC erratum reference for this ? Also it seems to make no
> sense
>
>
>>       static const struct ata_port_info info_rdc_11 = {
>>               .flags = ATA_FLAG_SLAVE_POSS,
>>               .pio_mask = ATA_PIO4,
>> -             .mwdma_mask = ATA_MWDMA2,
>> +             .mwdma_mask = 0,
>> +             .udma_mask = 0,
>
> MWDMA is not part of the CRC hardware anyway
>
> Are you sure these newer variants are simply not using a different set of
> timing parameters thus showing bugs on your system ?
>
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