AHCI: speed up resume (24920c8a) · Commits · 戴 / test

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>

drivers/ata/ahci.c

+6 −3

Original line number	Diff line number	Diff line
		@@ -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);

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