Hugh Dickins writes: > I've a Dell Precision 670 here (four-year-old EM64T Xeon with ata_piix) > which doesn't like your commit 871af1210f13966ab911ed2166e4ab2ce775b99d > libata: Add 32bit PIO support. Full dmesg (and .config) attached, but > here's an extract showing the start of the error messages on ata2: > > ata1: PATA max UDMA/100 cmd 0x1f0 ctl 0x3f6 bmdma 0xffa0 irq 14 > ata2: PATA max UDMA/100 cmd 0x170 ctl 0x376 bmdma 0xffa8 irq 15 > ata1: port disabled. ignoring. > ata2.00: ATAPI: GCR-8483B, 1.07, max UDMA/33 > ata2.00: configured for UDMA/33 > scsi 1:0:0:0: CD-ROM HL-DT-ST CD-ROM GCR-8483B 1.07 PQ: 0 ANSI: 5 > ata2.00: qc timeout (cmd 0xa0) > ata2.00: exception Emask 0x0 SAct 0x0 SErr 0x0 action 0x6 frozen > ata2.00: cmd a0/00:00:00:00:00/00:00:00:00:00/a0 tag 0 > cdb 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 > res 51/20:03:00:00:00/00:00:00:00:00/a0 Emask 0x5 (timeout) > ata2.00: status: { DRDY ERR } > ata2: soft resetting link > ata2.00: configured for UDMA/33 > ata2: EH complete > > linux-next behaved the same, so I played around, and the patch below seems > to fix it fine (though I've not yet tried it on other, working machines); > but I can well imagine you may prefer to do it differently. Or was I just > wrong to move that box's CD handling from ide to libata a few months ago? > > [PATCH] libata sff: 32bit PIO use 16bit on slop > > 871af1210f13966ab911ed2166e4ab2ce775b99d libata: Add 32bit PIO support > causes errors on a four-year-old ata_piix Dell Precision 670. Using > 16bit PIO instead of 32bit PIO on the odd 1, 2 or 3 chars fixes that. > > Signed-off-by: Hugh Dickins <hugh@xxxxxxxxxxx> > --- > > drivers/ata/libata-sff.c | 18 +++++++++++------- > 1 file changed, 11 insertions(+), 7 deletions(-) > > --- 2.6.29-rc2/drivers/ata/libata-sff.c 2009-01-17 10:40:12.000000000 +0000 > +++ linux/drivers/ata/libata-sff.c 2009-01-21 12:32:01.000000000 +0000 > @@ -774,17 +774,21 @@ unsigned int ata_sff_data_xfer32(struct > iowrite32_rep(data_addr, buf, words); > > if (unlikely(slop)) { > - __le32 pad; > + unsigned char slop_buf[4]; > + unsigned char *trailing_buf = buf + buflen - slop; > + > + words = (slop + 1) >> 1; > if (rw == READ) { > - pad = cpu_to_le32(ioread32(ap->ioaddr.data_addr)); > - memcpy(buf + buflen - slop, &pad, slop); > + ioread16_rep(data_addr, slop_buf, words); > + memcpy(trailing_buf, slop_buf, slop); > } else { > - memcpy(&pad, buf + buflen - slop, slop); > - iowrite32(le32_to_cpu(pad), ap->ioaddr.data_addr); > + memcpy(slop_buf, trailing_buf, slop); > + slop_buf[slop] = 0; > + iowrite16_rep(data_addr, slop_buf, words); > } > - words++; > } > - return words << 2; > + > + return buflen + (slop & 1); > } > EXPORT_SYMBOL_GPL(ata_sff_data_xfer32); Thanks, this patch also fixes the 2.6.29-rc bmdma32-related ata_piix regression I reported, where having a specific CD drive connected causes a complete system hang when init starts udev <http://marc.info/?l=linux-ide&m=123244042628229&w=2>. Tested-by: Mikael Pettersson <mikpe@xxxxxxxx> -- 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