This is a note to let you know that I've just added the patch titled
xhci: don't re-enable IE constantly
to the 3.0-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:
xhci-don-t-re-enable-ie-constantly.patch
and it can be found in the queue-3.0 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.
>From 4e833c0b87a30798e67f06120cecebef6ee9644c Mon Sep 17 00:00:00 2001
From: Felipe Balbi <[email protected]>
Date: Thu, 15 Mar 2012 16:37:08 +0200
Subject: xhci: don't re-enable IE constantly
From: Felipe Balbi <[email protected]>
commit 4e833c0b87a30798e67f06120cecebef6ee9644c upstream.
While we're at that, define IMAN bitfield to aid readability.
The interrupt enable bit should be set once on driver init, and we
shouldn't need to continually re-enable it. Commit c21599a3 introduced
a read of the irq_pending register, and that allows us to preserve the
state of the IE bit. Before that commit, we were blindly writing 0x3 to
the register.
This patch should be backported to kernels as old as 2.6.36, or ones
that contain the commit c21599a36165dbc78b380846b254017a548b9de5 "USB:
xhci: Reduce reads and writes of interrupter registers".
Signed-off-by: Felipe Balbi <[email protected]>
Signed-off-by: Sarah Sharp <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
drivers/usb/host/xhci-ring.c | 2 +-
drivers/usb/host/xhci.h | 4 ++++
2 files changed, 5 insertions(+), 1 deletion(-)
--- a/drivers/usb/host/xhci-ring.c
+++ b/drivers/usb/host/xhci-ring.c
@@ -2352,7 +2352,7 @@ hw_died:
u32 irq_pending;
/* Acknowledge the PCI interrupt */
irq_pending = xhci_readl(xhci, &xhci->ir_set->irq_pending);
- irq_pending |= 0x3;
+ irq_pending |= IMAN_IP;
xhci_writel(xhci, irq_pending, &xhci->ir_set->irq_pending);
}
--- a/drivers/usb/host/xhci.h
+++ b/drivers/usb/host/xhci.h
@@ -205,6 +205,10 @@ struct xhci_op_regs {
#define CMD_PM_INDEX (1 << 11)
/* bits 12:31 are reserved (and should be preserved on writes). */
+/* IMAN - Interrupt Management Register */
+#define IMAN_IP (1 << 1)
+#define IMAN_IE (1 << 0)
+
/* USBSTS - USB status - status bitmasks */
/* HC not running - set to 1 when run/stop bit is cleared. */
#define STS_HALT XHCI_STS_HALT
Patches currently in stable-queue which might be from [email protected] are
queue-3.0/xhci-don-t-re-enable-ie-constantly.patch
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