The patch below does not apply to the 3.10-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@xxxxxxxxxxxxxxx>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
>From 2cf532f5e67c0cfe38c8c100e49280cdadacd2be Mon Sep 17 00:00:00 2001
From: Alexander Gordeev <agordeev@xxxxxxxxxx>
Date: Thu, 17 Apr 2014 18:06:15 +0200
Subject: [PATCH] ahci: Do not receive interrupts sent by dummy ports
In multiple MSI mode all AHCI ports (including dummy) get assigned
separate MSI vectors and (as result of execution
pci_enable_msi_exact() function) separate IRQ numbers, (mapped to the
MSI vectors).
Therefore, although interrupts from dummy ports are not desired they
are still enabled. We do not request IRQs for dummy ports, but that
only means we do not assign AHCI-specific ISRs to corresponding IRQ
numbers.
As result, dummy port interrupts still could come and traverse all the
way from the PCI device to the kernel, causing unnecessary overhead.
This update disables IRQs for dummy ports and prevents the described
issue.
Signed-off-by: Alexander Gordeev <agordeev@xxxxxxxxxx>
Signed-off-by: Tejun Heo <tj@xxxxxxxxxx>
Tested-by: David Milburn <dmilburn@xxxxxxxxxx>
Cc: linux-ide@xxxxxxxxxxxxxxx
Cc: stable@xxxxxxxxxxxxxxx
Fixes: 5ca72c4f7c41 ("AHCI: Support multiple MSIs")
diff --git a/drivers/ata/ahci.c b/drivers/ata/ahci.c
index 44d40c746982..71e15b73513d 100644
--- a/drivers/ata/ahci.c
+++ b/drivers/ata/ahci.c
@@ -1241,12 +1241,16 @@ int ahci_host_activate(struct ata_host *host, int irq, unsigned int n_msis)
for (i = 0; i < host->n_ports; i++) {
struct ahci_port_priv *pp = host->ports[i]->private_data;
- /* pp is NULL for dummy ports */
- if (pp)
- rc = devm_request_threaded_irq(host->dev,
- irq + i, ahci_hw_interrupt,
- ahci_thread_fn, IRQF_SHARED,
- pp->irq_desc, host->ports[i]);
+ /* Do not receive interrupts sent by dummy ports */
+ if (!pp) {
+ disable_irq(irq + i);
+ continue;
+ }
+
+ rc = devm_request_threaded_irq(host->dev, irq + i,
+ ahci_hw_interrupt,
+ ahci_thread_fn, IRQF_SHARED,
+ pp->irq_desc, host->ports[i]);
if (rc)
goto out_free_irqs;
}
--
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