Re: [PATCH] sata_sil: combined irq + LBT DMA patch for testing

[Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>]

Hi,

On 1/18/06, Jeff Garzik <jgarzik@pobox.com> wrote:
> Thomas Backlund wrote:
> > Jeff Garzik wrote:
> >
> >> Thomas Backlund wrote:
> >>
> >>> Richard Bollinger wrote:
> >>>
> >>>>> ata1: BUG: SG size underflow
> >>>>> ata1: status=0x50 { DriveReady SeekComplete }
> >>>
> >>>
> >>>
> >>> and onde by one the raid devices got deactivated until the full
> >>> freeze...
> >>
> >>
> >>
> >> I think I know what's going on with the 'SG size underflow' thingy,
> >> give me a few days to come up with a fix.
> >>
> >>     Jeff
> >>
> >>
> >>
> > Any news on this?
> > or is it already fixed ?
>
> Back-burner for the moment :(

I think I have finally found the bug
after auditing the patch for x times...

+       /* Stop DMA, if doing DMA */
+       switch (qc->tf.protocol) {
+       case ATA_PROT_DMA:
+       case ATA_PROT_ATAPI_DMA:
+               ata_bmdma_stop(qc);

It should be sil_bmdma_stop()...

By accident ata_bmdma_stop() is OK for sil3112 so that would
explain why only people with sil3114 reported problems.

My theory is that using ata_bmdma_stop() for sil3114 results
in IRQs for port 2 and 3 not being delivered (because
SIL_INTR_STEERING bit is cleared) and we end up with
dma_stat_mask == 0.

Rest of the patch looks perfectly fine for me.  Could somebody
reporting problems with this patch retest with the above change?

+               break;
+       default:
+               /* do nothing */
+               break;
+       }

Bartlomiej
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