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 <tj@kernel.org>
Cc: Philipp Thomas <pth@novell.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
diff --git a/drivers/ata/ahci.c b/drivers/ata/ahci.c
index 6a4a2a2..061817a 100644
--- a/drivers/ata/ahci.c
+++ b/drivers/ata/ahci.c
@@ -1777,7 +1777,7 @@
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 @@
"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");