linux-kernel - [25/55] ahci: dont enable port irq before handler is registered

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Message-Id: <20110429185654.993077106@clark.kroah.org>
Date:	Fri, 29 Apr 2011 11:55:48 -0700
From:	Greg KH <gregkh@...e.de>
To:	linux-kernel@...r.kernel.org, stable@...nel.org
Cc:	stable-review@...nel.org, torvalds@...ux-foundation.org,
	akpm@...ux-foundation.org, alan@...rguk.ukuu.org.uk,
	Maxime Bizon <mbizon@...ebox.fr>, Tejun Heo <tj@...nel.org>,
	Jeff Garzik <jgarzik@...ox.com>
Subject: [25/55] ahci: dont enable port irq before handler is registered

2.6.38-stable review patch.  If anyone has any objections, please let us know.

------------------

From: Maxime Bizon <mbizon@...ebox.fr>

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 <mbizon@...ebox.fr>
Acked-by: Tejun Heo <tj@...nel.org>
Signed-off-by: Jeff Garzik <jgarzik@...ox.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...e.de>

---
 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;


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