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authorAlan Cox <alan@lxorguk.ukuu.org.uk>2007-08-08 15:27:00 +0200
committerJeff Garzik <jeff@garzik.org>2007-10-12 20:55:32 +0200
commit50a99018787aa1aed812e09ad5b27647475656a0 (patch)
tree371cfd54028da85abc8313cd72501541f7c6f06d
parentlibata: add support for ATA_16 on ATAPI (diff)
downloadlinux-50a99018787aa1aed812e09ad5b27647475656a0.tar.xz
linux-50a99018787aa1aed812e09ad5b27647475656a0.zip
libata-core: Document some limits/assumptions about ID_ATA
Signed-off-by: Alan Cox <alan@redhat.com> Signed-off-by: Jeff Garzik <jeff@garzik.org>
Diffstat (limited to '')
-rw-r--r--drivers/ata/libata-core.c10
1 files changed, 8 insertions, 2 deletions
diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index 75ccf46972d8..d2141a04fff1 100644
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -1618,6 +1618,9 @@ static u32 ata_pio_mask_no_iordy(const struct ata_device *adev)
* devices. This function also issues ATA_CMD_INIT_DEV_PARAMS
* for pre-ATA4 drives.
*
+ * FIXME: ATA_CMD_ID_ATA is optional for early drives and right
+ * now we abort if we hit that case.
+ *
* LOCKING:
* Kernel thread context (may sleep)
*
@@ -1745,10 +1748,13 @@ int ata_dev_read_id(struct ata_device *dev, unsigned int *p_class,
/*
* The exact sequence expected by certain pre-ATA4 drives is:
* SRST RESET
- * IDENTIFY
- * INITIALIZE DEVICE PARAMETERS
+ * IDENTIFY (optional in early ATA)
+ * INITIALIZE DEVICE PARAMETERS (later IDE and ATA)
* anything else..
* Some drives were very specific about that exact sequence.
+ *
+ * Note that ATA4 says lba is mandatory so the second check
+ * shoud never trigger.
*/
if (ata_id_major_version(id) < 4 || !ata_id_has_lba(id)) {
err_mask = ata_dev_init_params(dev, id[3], id[6]);