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

[Paul Schilling]

The Gmail web client wrapped the text on me.

Look at line 914 in drivers/ata/pata_it821x.c for references to the
Vortex86sx bug.

Thanks,
Paul

On Thu, Oct 27, 2011 at 1:55 PM, Paul Schilling
<paul.s.schilling@xxxxxxxxx> wrote:
> The Vortex86dx uses RDC IDE peripheral integrated into the SOC.  The
> CRC design is
> broken in the Vortex86dx and sx.  The original reference can be found
> in the Linux kernel itself.
>
> The Vortex86sx uses the RDC D1010.
> The Vortex86dx uses the RDC D1011.
> Both of which have broken CRC hardware which breaks DMA.
>
> The pata_821x.c had the following code in it to handle the RDC
> hardware used in the Vortex86SX.
>
> 4fca377f (Jeff Garzik               2011-02-15 01:13:24 -0500 913)
> 963e4975 (Alan Cox                  2008-07-24 17:16:06 +0100 914)
>  if (pdev->vendor == PCI_VENDOR_ID_RDC) {
> 4a99d95f (Alan Cox                  2009-01-11 19:51:08 +0000 915)
>         /* Deal with Vortex86SX */
> 4a99d95f (Alan Cox                  2009-01-11 19:51:08 +0000 916)
>         if (pdev->revision == 0x11)
> 4a99d95f (Alan Cox                  2009-01-11 19:51:08 +0000 917)
>                 ppi[0] = &info_rdc_11;
> 4a99d95f (Alan Cox                  2009-01-11 19:51:08 +0000 918)
>         else
> 4a99d95f (Alan Cox                  2009-01-11 19:51:08 +0000 919)
>                 ppi[0] = &info_rdc;
> 963e4975 (Alan Cox                  2008-07-24 17:16:06 +0100 920)      } else {
> 963e4975 (Alan Cox                  2008-07-24 17:16:06 +0100 921)
>         /* Force the card into bypass mode if so requested */
> 963e4975 (Alan Cox                  2008-07-24 17:16:06 +0100 922)
>         if (it8212_noraid) {
> 963e4975 (Alan Cox                  2008-07-24 17:16:06 +0100 923)
>                 printk(KERN_INFO DRV_NAME ": forcing bypass
> mode.\n");
> 963e4975 (Alan Cox                  2008-07-24 17:16:06 +0100 924)
>                 it821x_disable_raid(pdev);
>
> Thanks,
> Paul Schilling
>
> 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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