From 50a99018787aa1aed812e09ad5b27647475656a0 Mon Sep 17 00:00:00 2001 From: Alan Cox Date: Wed, 8 Aug 2007 14:27:00 +0100 Subject: [PATCH] libata-core: Document some limits/assumptions about ID_ATA Signed-off-by: Alan Cox Signed-off-by: Jeff Garzik --- drivers/ata/libata-core.c | 10 ++++++++-- 1 file 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]);