The patch titled
pm: ahci: speed up resume
has been added to the -mm tree. Its filename is
pm-ahci-speed-up-resume.patch
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The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/
------------------------------------------------------
Subject: pm: ahci: speed up resume
From: Zhang Rui <rui.zhang@xxxxxxxxx>
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@xxxxxxxxx>
Acked-by: Tejun Heo <tj@xxxxxxxxxx>
Signed-off-by: Rafael J. Wysocki <rjw@xxxxxxx>
Cc: Jeff Garzik <jeff@xxxxxxxxxx>
Acked-by: Pavel Machek <pavel@xxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
drivers/ata/ahci.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)
diff -puN drivers/ata/ahci.c~pm-ahci-speed-up-resume drivers/ata/ahci.c
--- a/drivers/ata/ahci.c~pm-ahci-speed-up-resume
+++ a/drivers/ata/ahci.c
@@ -1142,12 +1142,15 @@ static int ahci_reset_controller(struct
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);
_
Patches currently in -mm which might be from rui.zhang@xxxxxxxxx are
linux-next.patch
pm-ahci-speed-up-resume.patch
pm-introduce-new-interfaces-schedule_work_on-and-queue_work_on.patch
pm-schedule-sysrq-poweroff-on-boot-cpu.patch
dcdbas-use-memory_read_from_buffer.patch
dell_rbu-use-memory_read_from_buffer.patch
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