diff options
Diffstat (limited to 'drivers/scsi/libata-core.c')
| -rw-r--r-- | drivers/scsi/libata-core.c | 31 |
1 files changed, 27 insertions, 4 deletions
diff --git a/drivers/scsi/libata-core.c b/drivers/scsi/libata-core.c index 175d464..09639e7 100644 --- a/drivers/scsi/libata-core.c +++ b/drivers/scsi/libata-core.c @@ -1082,6 +1082,31 @@ static inline void ata_dump_id(struct ata_device *dev) dev->id[93]); } +/* + * Compute the PIO modes available for this device. This is not as + * trivial as it seems if we must consider early devices correctly. + * + * FIXME: pre IDE drive timing (do we care ?). + */ + +static unsigned int ata_pio_modes(struct ata_device *adev) +{ + u16 modes; + + /* Usual case. Word 53 indicates word 88 is valid */ + if (adev->id[ATA_ID_FIELD_VALID] & (1 << 2)) { + modes = adev->id[ATA_ID_PIO_MODES] & 0x03; + modes <<= 3; + modes |= 0x7; + return modes; + } + + /* If word 88 isn't valid then Word 51 holds the PIO timing number + for the maximum. Turn it into a mask and return it */ + modes = (2 << (adev->id[ATA_ID_OLD_PIO_MODES] & 0xFF)) - 1 ; + return modes; +} + /** * ata_dev_identify - obtain IDENTIFY x DEVICE page * @ap: port on which device we wish to probe resides @@ -1215,10 +1240,8 @@ retry: xfer_modes = dev->id[ATA_ID_UDMA_MODES]; if (!xfer_modes) xfer_modes = (dev->id[ATA_ID_MWDMA_MODES]) << ATA_SHIFT_MWDMA; - if (!xfer_modes) { - xfer_modes = (dev->id[ATA_ID_PIO_MODES]) << (ATA_SHIFT_PIO + 3); - xfer_modes |= (0x7 << ATA_SHIFT_PIO); - } + if (!xfer_modes) + xfer_modes = ata_pio_modes(dev); ata_dump_id(dev); |