From 4e833c0b87a30798e67f06120cecebef6ee9644c Mon Sep 17 00:00:00 2001 From: Felipe Balbi Date: Thu, 15 Mar 2012 16:37:08 +0200 Subject: [PATCH] xhci: don't re-enable IE constantly 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 Signed-off-by: Sarah Sharp Cc: stable@vger.kernel.org --- drivers/usb/host/xhci-ring.c | 2 +- drivers/usb/host/xhci.h | 4 ++++ 2 files changed, 5 insertions(+), 1 deletion(-) diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c index 6bd9d53062eb..5ddc4ae85499 100644 --- a/drivers/usb/host/xhci-ring.c +++ b/drivers/usb/host/xhci-ring.c @@ -2417,7 +2417,7 @@ 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); } diff --git a/drivers/usb/host/xhci.h b/drivers/usb/host/xhci.h index 91074fdab3eb..3d69c4b2b542 100644 --- 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 -- 2.20.1