From 0ee719527229fa86ace8e3abccae3c2a8bbfd6db Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Mon, 7 Jun 2010 15:15:08 +0200 Subject: [PATCH] ahci: redo stopping DMA engines on empty ports Commit 96d60303fd (ahci: Turn off DMA engines when there's no device) implemented stopping DMA engines on empty ports but it used single sampling of status registers to determine device presence which led to disabling of DMA engines on occupied ports. Do it after all EH actions are complete using device presence state determined by EH. This avoids spurious disabling of DMA engines and simplifies the code. Signed-off-by: Tejun Heo Tested-by: Marc Dionne Cc: Matthew Garrett Cc: Robert Hancock Signed-off-by: Jeff Garzik --- drivers/ata/libahci.c | 21 +++------------------ 1 file changed, 3 insertions(+), 18 deletions(-) diff --git a/drivers/ata/libahci.c b/drivers/ata/libahci.c index 1984a6e89e84..261f86d102e8 100644 --- a/drivers/ata/libahci.c +++ b/drivers/ata/libahci.c @@ -541,29 +541,11 @@ static int ahci_scr_write(struct ata_link *link, unsigned int sc_reg, u32 val) return -EINVAL; } -static int ahci_is_device_present(void __iomem *port_mmio) -{ - u8 status = readl(port_mmio + PORT_TFDATA) & 0xff; - - /* Make sure PxTFD.STS.BSY and PxTFD.STS.DRQ are 0 */ - if (status & (ATA_BUSY | ATA_DRQ)) - return 0; - - /* Make sure PxSSTS.DET is 3h */ - status = readl(port_mmio + PORT_SCR_STAT) & 0xf; - if (status != 3) - return 0; - return 1; -} - void ahci_start_engine(struct ata_port *ap) { void __iomem *port_mmio = ahci_port_base(ap); u32 tmp; - if (!ahci_is_device_present(port_mmio)) - return; - /* start DMA */ tmp = readl(port_mmio + PORT_CMD); tmp |= PORT_CMD_START; @@ -1892,6 +1874,9 @@ static void ahci_error_handler(struct ata_port *ap) } sata_pmp_error_handler(ap); + + if (!ata_dev_enabled(ap->link.device)) + ahci_stop_engine(ap); } static void ahci_post_internal_cmd(struct ata_queued_cmd *qc) -- 2.20.1