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| author | Sergei Shtylyov <sshtylyov@ru.mvista.com> | 2009-02-15 23:24:24 +0400 |
|---|---|---|
| committer | Jeff Garzik <jgarzik@redhat.com> | 2009-02-16 18:55:56 -0500 |
| commit | d1b3525b4126d7acad0493b62642b80b71442661 (patch) | |
| tree | e8b55a52e5a57f92b997f84365fa9a72ded106c8 /drivers | |
| parent | d2f8d7ee1a9b4650b4e43325b321801264f7c37a (diff) | |
| download | lwn-d1b3525b4126d7acad0493b62642b80b71442661.tar.gz lwn-d1b3525b4126d7acad0493b62642b80b71442661.zip | |
libata-sff: fix 32-bit PIO ATAPI regression
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@ru.mvista.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/ata/libata-sff.c | 28 |
1 files changed, 21 insertions, 7 deletions
diff --git a/drivers/ata/libata-sff.c b/drivers/ata/libata-sff.c index 0b299b0f8172..714cb046b594 100644 --- a/drivers/ata/libata-sff.c +++ b/drivers/ata/libata-sff.c @@ -773,18 +773,32 @@ unsigned int ata_sff_data_xfer32(struct ata_device *dev, unsigned char *buf, 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); |