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AHCI: speed up resume 

During resume, sleep 1 second to wait for the HBA reset
to finish is a waste of time.

According to the AHCI 1.2 spec,
We should poll the HOST_CTL register,
and return error if the host reset is not
finished within 1 second.

Test results show that the HBA reset can be done quickly(in usecs).
And this patch may save nearly 1 second during resume.

Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
This commit is contained in:
Zhang Rui 2008-07-04 13:32:17 +08:00 committed by Jeff Garzik
parent 1e9dbc9291
commit 24920c8a63
1 changed files with 6 additions and 3 deletions
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9
drivers/ata/ahci.c
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@ -1142,12 +1142,15 @@ static int ahci_reset_controller(struct ata_host *host)
readl(mmio + HOST_CTL); /* flush */
}
/* reset must complete within 1 second, or
/*
* to perform host reset, OS should set HOST_RESET
* and poll until this bit is read to be "0".
* reset must complete within 1 second, or
* the hardware should be considered fried.
*/
ssleep(1);
tmp = ata_wait_register(mmio + HOST_CTL, HOST_RESET,
HOST_RESET, 10, 1000);
tmp = readl(mmio + HOST_CTL);
if (tmp & HOST_RESET) {
dev_printk(KERN_ERR, host->dev,
"controller reset failed (0x%x)\n", tmp);