On Sun, 28 Oct 2007 12:03:16 +0100 (MET), Mikael Pettersson wrote:
> On Sun, 28 Oct 2007 06:29:32 -0400, Jeff Garzik wrote:
> > BTW, looking at the Promise code I see
> >
> > > cam_con.h:
> > > /* for ASIC bug, limit the last element of SG byteCount must < 32 Dword */
> > > #define SG_COUNT_ASIC_BUG 32
> > > //#define SG_COUNT_ASIC_BUG 128
> >
> > and in the code itself
> >
> > > /* check PRD table, last element <= (32 Dword), fix ASIC bug */
> >
> > (though the code obviously uses SG_COUNT_ASIC_BUG==32, as the first
> > paste indicates)
> >
> > so it seems like Promise first used 128 (32 dwords), but then backed
> > down to 32 (8 dwords).
> >
> > Either way, we definitely have an ASIC bug to work around, it seems...
>
> You're looking at the old pdc-ultra2 driver. The newer unified
> sataii150-300 driver (v1.01.0.23) upped the value to 41*4.
>
> I've reviewed Alexander's patch, and I'm currently testing it
> with the add-on patch below (fix sg_tablesize, code formatting
> stuff, fix uninitialised 'addr' in a VPRINTK).
FYI:
Several hours of testing on a SATA300 TX4 with two 3Gbps disks went well,
as did a quick test on a SATA300 TX2plus with one SATA and one PATA disk.
I'll test further on a 1st generation controller tomorrow.
>
> /Mikael
>
> --- linux-2.6.24-rc1/drivers/ata/sata_promise.c.~1~ 2007-10-28 11:58:01.000000000 +0100
> +++ linux-2.6.24-rc1/drivers/ata/sata_promise.c 2007-10-28 12:20:53.000000000 +0100
> @@ -155,7 +155,7 @@ static struct scsi_host_template pdc_ata
> .queuecommand = ata_scsi_queuecmd,
> .can_queue = ATA_DEF_QUEUE,
> .this_id = ATA_SHT_THIS_ID,
> - .sg_tablesize = LIBATA_MAX_PRD,
> + .sg_tablesize = LIBATA_MAX_PRD-1,
> .cmd_per_lun = ATA_SHT_CMD_PER_LUN,
> .emulated = ATA_SHT_EMULATED,
> .use_clustering = ATA_SHT_USE_CLUSTERING,
> @@ -542,7 +542,7 @@ static void pdc_fill_sg(struct ata_queue
>
> if (!(qc->flags & ATA_QCFLAG_DMAMAP))
> return;
> -
> +
> WARN_ON(qc->__sg == NULL);
> WARN_ON(qc->n_elem == 0 && qc->pad_len == 0);
>
> @@ -579,18 +579,15 @@ static void pdc_fill_sg(struct ata_queue
>
> if (len > SG_COUNT_ASIC_BUG) {
> u32 addr;
> - /* if len < 2*SG_COUNT_ASIC_BUG then last
> - segment will be larger than next-to-last.
> - Somewhat ugly :(
> - */
>
> VPRINTK("Splitting last PRD.\n");
>
> + addr = le32_to_cpu(ap->prd[idx - 1].addr);
> ap->prd[idx - 1].flags_len -= cpu_to_le32(SG_COUNT_ASIC_BUG);
> VPRINTK("PRD[%u] = (0x%X, 0x%X)\n", idx - 1, addr, SG_COUNT_ASIC_BUG);
> -
> - addr = le32_to_cpu(ap->prd[idx - 1].addr) + len - SG_COUNT_ASIC_BUG;
> - len = SG_COUNT_ASIC_BUG;
> +
> + addr = addr + len - SG_COUNT_ASIC_BUG;
> + len = SG_COUNT_ASIC_BUG;
> ap->prd[idx].addr = cpu_to_le32(addr);
> ap->prd[idx].flags_len = cpu_to_le32(len);
> VPRINTK("PRD[%u] = (0x%X, 0x%X)\n", idx, addr, len);
> -
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