The original workaround for the Promise ASIC PRD bug
contained an endianess bug which I failed to detect:
the adjustment of the last PRD entry's length field
applied host arithmetic to little-endian data, which
is incorrect on big-endian machines.
We have the length available in host-endian format, so
do the adjustment on host-endian data and then convert
and store it in the PRD entry's little-endian data field.
Thanks to an anonymous reviewer for detecting this bug.
Signed-off-by: Mikael Pettersson <mikpe@xxxxxxxx>
---
Jeff: please include this fix in any backport(s) of the
ASIC PRD bug workaround.
drivers/ata/sata_promise.c | 2 +-
1 files changed, 1 insertion(+), 1 deletion(-)
diff -rupN linux-2.6.24-rc1/drivers/ata/sata_promise.c linux-2.6.24-rc1.sata_promise-endianess-fix/drivers/ata/sata_promise.c
--- linux-2.6.24-rc1/drivers/ata/sata_promise.c 2007-10-31 11:47:13.000000000 +0100
+++ linux-2.6.24-rc1.sata_promise-endianess-fix/drivers/ata/sata_promise.c 2007-10-31 11:47:25.000000000 +0100
@@ -585,7 +585,7 @@ static void pdc_fill_sg(struct ata_queue
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);
+ ap->prd[idx - 1].flags_len = cpu_to_le32(len - SG_COUNT_ASIC_BUG);
VPRINTK("PRD[%u] = (0x%X, 0x%X)\n", idx - 1, addr, SG_COUNT_ASIC_BUG);
addr = addr + len - SG_COUNT_ASIC_BUG;
-
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