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Subject[RFC 2/4] libata: Remove excess delay in the tf_load path
Date
We don't need to stall and wait after loading the task file and before
issuing a command, so don't do it. This shows up on profiles and is not
needed. It costs us up to 1mS on a dumb controller. Matches the old IDE
behaviour.

[Note we are now at 2mS on a dumb controller of what seems to be excess
delay and fiddling, 3mS if you are writing ctl]

Signed-off-by: Alan Cox <alan@linux.intel.com>
---
drivers/ata/libata-sff.c | 3 ---
drivers/ata/pata_via.c | 2 --
2 files changed, 0 insertions(+), 5 deletions(-)

diff --git a/drivers/ata/libata-sff.c b/drivers/ata/libata-sff.c
index cf0332a..3558ca8 100644
--- a/drivers/ata/libata-sff.c
+++ b/drivers/ata/libata-sff.c
@@ -579,7 +579,6 @@ void ata_sff_tf_load(struct ata_port *ap, const struct ata_taskfile *tf)
if (ioaddr->ctl_addr)
iowrite8(tf->ctl, ioaddr->ctl_addr);
ap->last_ctl = tf->ctl;
- ata_wait_idle(ap);
}

if (is_addr && (tf->flags & ATA_TFLAG_LBA48)) {
@@ -615,8 +614,6 @@ void ata_sff_tf_load(struct ata_port *ap, const struct ata_taskfile *tf)
iowrite8(tf->device, ioaddr->device_addr);
VPRINTK("device 0x%X\n", tf->device);
}
-
- ata_wait_idle(ap);
}
EXPORT_SYMBOL_GPL(ata_sff_tf_load);

diff --git a/drivers/ata/pata_via.c b/drivers/ata/pata_via.c
index 6356377..eccfed2 100644
--- a/drivers/ata/pata_via.c
+++ b/drivers/ata/pata_via.c
@@ -416,8 +416,6 @@ static void via_tf_load(struct ata_port *ap, const struct ata_taskfile *tf)
tf->lbam,
tf->lbah);
}
-
- ata_wait_idle(ap);
}

static int via_port_start(struct ata_port *ap)


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