src/patches/suse-2.6.27.39/patches.drivers/libata-add-and-use-HORKAGE_ATAPI_MOD16_DMA

   1 From 6a87e42e955ff27e07a77f65f8f077dc7c4171e1 Mon Sep 17 00:00:00 2001
   2 From: Tejun Heo <tj@kernel.org>
   3 Date: Mon, 3 Nov 2008 19:01:09 +0900
   4 Subject: [PATCH] libata: implement ATA_HORKAGE_ATAPI_MOD16_DMA and apply it
   5
   6 libata always uses PIO for ATAPI commands when the number of bytes to
   7 transfer isn't multiple of 16 but quantum DAT72 chokes on odd bytes
   8 PIO transfers.  Implement a horkage to skip the mod16 check and apply
   9 it to the quantum device.
  10
  11 This is reported by John Clark in the following thread.
  12
  13   http://thread.gmane.org/gmane.linux.ide/34748
  14
  15 Signed-off-by: Tejun Heo <tj@kernel.org>
  16 Cc: John Clark <clarkjc@runbox.com>
  17 Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
  18 Signed-off-by: Tejun Heo <teheo@suse.de>
  19 ---
  20  drivers/ata/libata-core.c |    4 +++-
  21  include/linux/libata.h    |    2 ++
  22  2 files changed, 5 insertions(+), 1 deletion(-)
  23
  24 --- a/drivers/ata/libata-core.c
  25 +++ b/drivers/ata/libata-core.c
  26 @@ -4036,6 +4036,7 @@ static const struct ata_blacklist_entry
  27
  28         /* Weird ATAPI devices */
  29         { "TORiSAN DVD-ROM DRD-N216", NULL,     ATA_HORKAGE_MAX_SEC_128 },
  30 +       { "QUANTUM DAT    DAT72-000", NULL,     ATA_HORKAGE_ATAPI_MOD16_DMA },
  31
  32         /* Devices we expect to fail diagnostics */
  33
  34 @@ -4519,7 +4520,8 @@ int atapi_check_dma(struct ata_queued_cm
  35         /* Don't allow DMA if it isn't multiple of 16 bytes.  Quite a
  36          * few ATAPI devices choke on such DMA requests.
  37          */
  38 -       if (unlikely(qc->nbytes & 15))
  39 +       if (!(qc->dev->horkage & ATA_HORKAGE_ATAPI_MOD16_DMA) &&
  40 +           unlikely(qc->nbytes & 15))
  41                 return 1;
  42
  43         if (ap->ops->check_atapi_dma)
  44 --- a/include/linux/libata.h
  45 +++ b/include/linux/libata.h
  46 @@ -372,6 +372,8 @@ enum {
  47         ATA_HORKAGE_IVB         = (1 << 8),     /* cbl det validity bit bugs */
  48         ATA_HORKAGE_STUCK_ERR   = (1 << 9),     /* stuck ERR on next PACKET */
  49         ATA_HORKAGE_BRIDGE_OK   = (1 << 10),    /* no bridge limits */
  50 +       ATA_HORKAGE_ATAPI_MOD16_DMA = (1 << 11), /* use ATAPI DMA for commands
  51 +                                                   not multiple of 16 bytes */
  52         ATA_HORKAGE_FIRMWARE_WARN = (1 << 12),  /* firwmare update warning */
  53
  54          /* DMA mask for user DMA control: User visible values; DO NOT