Pavel Machek wrote:
--- a/drivers/ata/ahci.c
+++ b/drivers/ata/ahci.c
@@ -148,6 +148,8 @@ enum {
PORT_IRQ_PIOS_FIS | PORT_IRQ_D2H_REG_FIS,
/* PORT_CMD bits */
+ PORT_CMD_ALPE = (1 << 27), /* Aggressive Link Power Management Enable */
+ PORT_CMD_ASP = (1 << 26), /* Aggressive entrance to Slumber or Partial power management states */
PORT_CMD_ATAPI = (1 << 24), /* Device is ATAPI */
PORT_CMD_LIST_ON = (1 << 15), /* cmd list DMA engine running */
PORT_CMD_FIS_ON = (1 << 14), /* FIS DMA engine running */
@@ -486,7 +488,7 @@ static void ahci_power_up(void __iomem *
}
/* wake up link */
- writel(cmd | PORT_CMD_ICC_ACTIVE, port_mmio + PORT_CMD);
+ writel(cmd | PORT_CMD_ICC_ACTIVE | PORT_CMD_ALPE | PORT_CMD_ASP, port_mmio + PORT_CMD);
Therein lies a key problem. Turning on all of AHCI's aggressive power
management features DOES save a lot of power. But at the same time, it
shortens the life of your hard drive, particularly hard drives that are
really PATA, but have a PATA<->SATA bridge glued on the drive to enable
connection to SATA controllers.
Jeff
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