This is a note to let you know that I've just added the patch titled
ahci: Do not receive interrupts sent by dummy ports
to the 3.14-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
ahci-do-not-receive-interrupts-sent-by-dummy-ports.patch
and it can be found in the queue-3.14 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 2cf532f5e67c0cfe38c8c100e49280cdadacd2be Mon Sep 17 00:00:00 2001
From: Alexander Gordeev <agordeev@xxxxxxxxxx>
Date: Thu, 17 Apr 2014 18:06:15 +0200
Subject: ahci: Do not receive interrupts sent by dummy ports
From: Alexander Gordeev <agordeev@xxxxxxxxxx>
commit 2cf532f5e67c0cfe38c8c100e49280cdadacd2be upstream.
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
Fixes: 5ca72c4f7c41 ("AHCI: Support multiple MSIs")
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/ata/ahci.c | 16 ++++++++++------
1 file changed, 10 insertions(+), 6 deletions(-)
--- a/drivers/ata/ahci.c
+++ b/drivers/ata/ahci.c
@@ -1242,12 +1242,16 @@ int ahci_host_activate(struct ata_host *
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;
}
Patches currently in stable-queue which might be from agordeev@xxxxxxxxxx are
queue-3.14/ahci-do-not-request-irq-for-dummy-port.patch
queue-3.14/ahci-ensure-msi-revert-to-single-message-mode-is-not-enforced.patch
queue-3.14/ahci-do-not-receive-interrupts-sent-by-dummy-ports.patch
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