This is a note to let you know that I've just added the patch titled

    ahci: don't enable port irq before handler is registered

to the 2.6.38-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-don-t-enable-port-irq-before-handler-is-registered.patch
and it can be found in the queue-2.6.38 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.


>From 7b3a24c57d2eeda8dba9c205342b12689c4679f9 Mon Sep 17 00:00:00 2001
From: Maxime Bizon <[email protected]>
Date: Wed, 16 Mar 2011 14:58:32 +0100
Subject: ahci: don't enable port irq before handler is registered

From: Maxime Bizon <[email protected]>

commit 7b3a24c57d2eeda8dba9c205342b12689c4679f9 upstream.

The ahci_pmp_attach() & ahci_pmp_detach() unmask port irqs, but they
are also called during port initialization, before ahci host irq
handler is registered. On ce4100 platform, this sometimes triggers
"irq 4: nobody cared" message when loading driver.

Fixed this by not touching the register if the port is in frozen
state, and mark all uninitialized port as frozen.

Signed-off-by: Maxime Bizon <[email protected]>
Acked-by: Tejun Heo <[email protected]>
Signed-off-by: Jeff Garzik <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

---
 drivers/ata/libahci.c     |   17 +++++++++++++++--
 drivers/ata/libata-core.c |    4 ++--
 2 files changed, 17 insertions(+), 4 deletions(-)

--- a/drivers/ata/libahci.c
+++ b/drivers/ata/libahci.c
@@ -1897,7 +1897,17 @@ static void ahci_pmp_attach(struct ata_p
        ahci_enable_fbs(ap);
 
        pp->intr_mask |= PORT_IRQ_BAD_PMP;
-       writel(pp->intr_mask, port_mmio + PORT_IRQ_MASK);
+
+       /*
+        * We must not change the port interrupt mask register if the
+        * port is marked frozen, the value in pp->intr_mask will be
+        * restored later when the port is thawed.
+        *
+        * Note that during initialization, the port is marked as
+        * frozen since the irq handler is not yet registered.
+        */
+       if (!(ap->pflags & ATA_PFLAG_FROZEN))
+               writel(pp->intr_mask, port_mmio + PORT_IRQ_MASK);
 }
 
 static void ahci_pmp_detach(struct ata_port *ap)
@@ -1913,7 +1923,10 @@ static void ahci_pmp_detach(struct ata_p
        writel(cmd, port_mmio + PORT_CMD);
 
        pp->intr_mask &= ~PORT_IRQ_BAD_PMP;
-       writel(pp->intr_mask, port_mmio + PORT_IRQ_MASK);
+
+       /* see comment above in ahci_pmp_attach() */
+       if (!(ap->pflags & ATA_PFLAG_FROZEN))
+               writel(pp->intr_mask, port_mmio + PORT_IRQ_MASK);
 }
 
 int ahci_port_resume(struct ata_port *ap)
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -5479,8 +5479,8 @@ struct ata_port *ata_port_alloc(struct a
        ap = kzalloc(sizeof(*ap), GFP_KERNEL);
        if (!ap)
                return NULL;
-       
-       ap->pflags |= ATA_PFLAG_INITIALIZING;
+
+       ap->pflags |= ATA_PFLAG_INITIALIZING | ATA_PFLAG_FROZEN;
        ap->lock = &host->lock;
        ap->print_id = -1;
        ap->host = host;


Patches currently in stable-queue which might be from [email protected] are

queue-2.6.38/ahci-don-t-enable-port-irq-before-handler-is-registered.patch

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