Commit 871af1210f13966ab911ed2166e4ab2ce775b99d (libata: Add 32bit PIO support) has caused all kinds of errors on the ATAPI devices, so it has been empirically proven that one shouldn't try to read/write an extra data word when a device is not expecting it already. "Don't do it then"; however, still use a chance to do 32-bit read/write one last time when there are exactly 3 trailing bytes. Oh, and stop pointlessly swapping the bytes to and fro on big-endian machines by using io*_rep() accessors which shouldn't byte-swap. This patch should fix the kernel.org bug #12609. Signed-off-by: Sergei Shtylyov <sshtylyov@xxxxxxxxxxxxx> --- Added the comments and signoff. The patch is against the recent Linus' tree. It's a hopefully better replacement for Hugh Dickins most recent patch (http://marc.info/?l=linux-ide&m=123352294619281)... drivers/ata/libata-sff.c | 28 +++++++++++++++++++++------- 1 files changed, 21 insertions(+), 7 deletions(-) Index: linux-2.6/drivers/ata/libata-sff.c =================================================================== --- linux-2.6.orig/drivers/ata/libata-sff.c +++ linux-2.6/drivers/ata/libata-sff.c @@ -773,18 +773,32 @@ unsigned int ata_sff_data_xfer32(struct else iowrite32_rep(data_addr, buf, words); + /* Transfer trailing bytes, if any */ if (unlikely(slop)) { - __le32 pad; + unsigned char pad[4]; + + /* Point buf to the tail of buffer */ + buf += buflen - slop; + + /* + * Use io*_rep() accessors here as well to avoid pointlessly + * swapping bytes to and fro on the big endian machines... + */ if (rw == READ) { - pad = cpu_to_le32(ioread32(ap->ioaddr.data_addr)); - memcpy(buf + buflen - slop, &pad, slop); + if (slop < 3) + ioread16_rep(data_addr, pad, 1); + else + ioread32_rep(data_addr, pad, 1); + memcpy(buf, pad, slop); } else { - memcpy(&pad, buf + buflen - slop, slop); - iowrite32(le32_to_cpu(pad), ap->ioaddr.data_addr); + memcpy(pad, buf, slop); + if (slop < 3) + iowrite16_rep(data_addr, pad, 1); + else + iowrite32_rep(data_addr, pad, 1); } - words++; } - return words << 2; + return (buflen + 1) & ~1; } EXPORT_SYMBOL_GPL(ata_sff_data_xfer32); -- To unsubscribe from this list: send the line "unsubscribe linux-ide" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
