From ea0c62f7cf70f13a67830471b613337bd0c9a62e Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Sat, 28 Jun 2008 01:49:02 +0900 Subject: ahci: always clear all bits in irq_stat Some AHCI controllers (ICH7 was reported) set pending bit in HOST_IRQ_STAT for non-existent ports and when it's not cleared falls into IRQ storm. Always clear full irq_stat instead of only the bits that are handled. As nothing changes for recognized ports, the risk of breaking things is pretty low. Reported and verified by Philipp Thomas in the following suse bugzilla. https://bugzilla.novell.com/attachment.cgi?id=215692 Signed-off-by: Tejun Heo Cc: Philipp Thomas Signed-off-by: Jeff Garzik --- drivers/ata/ahci.c | 9 +++------ 1 file changed, 3 insertions(+), 6 deletions(-) (limited to 'drivers/ata/ahci.c') diff --git a/drivers/ata/ahci.c b/drivers/ata/ahci.c index 6a4a2a25d97..061817a3a0e 100644 --- a/drivers/ata/ahci.c +++ b/drivers/ata/ahci.c @@ -1777,7 +1777,7 @@ static irqreturn_t ahci_interrupt(int irq, void *dev_instance) struct ahci_host_priv *hpriv; unsigned int i, handled = 0; void __iomem *mmio; - u32 irq_stat, irq_ack = 0; + u32 irq_stat; VPRINTK("ENTER\n"); @@ -1809,14 +1809,11 @@ static irqreturn_t ahci_interrupt(int irq, void *dev_instance) "interrupt on disabled port %u\n", i); } - irq_ack |= (1 << i); - } - - if (irq_ack) { - writel(irq_ack, mmio + HOST_IRQ_STAT); handled = 1; } + writel(irq_stat, mmio + HOST_IRQ_STAT); + spin_unlock(&host->lock); VPRINTK("EXIT\n"); -- cgit v1.2.3 From d28f87aa87ce8b196349d7c306a7e6fe3abd7155 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Sat, 5 Jul 2008 13:10:50 +0900 Subject: ahci: give another shot at clearing all bits in irq_stat Commit ea0c62f7cf70f13a67830471b613337bd0c9a62e tried to clear all bits in irq_stat but it didn't actually achieve that as irq_stat was anded with port_map right after read. This patch makes ahci driver always use the unmasked value to clear irq_status. While at it, add explanation on the peculiarities of ahci IRQ clearing. This was spotted by Linus Torvalds. Signed-off-by: Tejun Heo Signed-off-by: Linus Torvalds --- drivers/ata/ahci.c | 16 +++++++++++++--- 1 file changed, 13 insertions(+), 3 deletions(-) (limited to 'drivers/ata/ahci.c') diff --git a/drivers/ata/ahci.c b/drivers/ata/ahci.c index 061817a3a0e..5e6468a7ca4 100644 --- a/drivers/ata/ahci.c +++ b/drivers/ata/ahci.c @@ -1777,7 +1777,7 @@ static irqreturn_t ahci_interrupt(int irq, void *dev_instance) struct ahci_host_priv *hpriv; unsigned int i, handled = 0; void __iomem *mmio; - u32 irq_stat; + u32 irq_stat, irq_masked; VPRINTK("ENTER\n"); @@ -1786,16 +1786,17 @@ static irqreturn_t ahci_interrupt(int irq, void *dev_instance) /* sigh. 0xffffffff is a valid return from h/w */ irq_stat = readl(mmio + HOST_IRQ_STAT); - irq_stat &= hpriv->port_map; if (!irq_stat) return IRQ_NONE; + irq_masked = irq_stat & hpriv->port_map; + spin_lock(&host->lock); for (i = 0; i < host->n_ports; i++) { struct ata_port *ap; - if (!(irq_stat & (1 << i))) + if (!(irq_masked & (1 << i))) continue; ap = host->ports[i]; @@ -1812,6 +1813,15 @@ static irqreturn_t ahci_interrupt(int irq, void *dev_instance) handled = 1; } + /* HOST_IRQ_STAT behaves as level triggered latch meaning that + * it should be cleared after all the port events are cleared; + * otherwise, it will raise a spurious interrupt after each + * valid one. Please read section 10.6.2 of ahci 1.1 for more + * information. + * + * Also, use the unmasked value to clear interrupt as spurious + * pending event on a dummy port might cause screaming IRQ. + */ writel(irq_stat, mmio + HOST_IRQ_STAT); spin_unlock(&host->lock); -- cgit v1.2.3