irq is disabled in xhci_quiesce(called by xhci_halt, with bit:2 cleared
in USBCMD register), but xhci_run(called by usb_add_hcd) re-enable it.
It's possible that you will receive thousands of interrupt requests
after initialization for 2.0 roothub. And you will get a lot of
warning like, "xHCI dying, ignoring interrupt. Shouldn't IRQs be
disabled?". This amount of interrupt requests will cause the entire
system to freeze.
This problem was first found on a device with ASM2142 host controller
on it.
Signed-off-by: Hongyu Xie <xiehongyu1@xxxxxxxxxx>
---
v3:
- enabling interrupt right before setting Run/Stop bit
- spin_lock_irqsave to prevent receiving irqs in the small window
according to Mathias's suggestion
v2: fix compile error
drivers/usb/host/xhci.c | 40 ++++++++++++++++++++++++++--------------
1 file changed, 26 insertions(+), 14 deletions(-)
diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
index 9ac56e9ffc64..5cf8baa4f6f3 100644
--- a/drivers/usb/host/xhci.c
+++ b/drivers/usb/host/xhci.c
@@ -611,15 +611,40 @@ static int xhci_init(struct usb_hcd *hcd)
static int xhci_run_finished(struct xhci_hcd *xhci)
{
+ u32 temp;
+
+ /* Prevent receiving irqs in the small window between enabling interrupt
+ * and setting Run/Stop bit
+ */
+ spin_lock_irqsave(&xhci->lock, flags);
+
+ /* Enable interrupt right before setting Run/Stop bit according to spec
+ * 4.2
+ */
+ /* Set the HCD state before we enable the irqs */
+ temp = readl(&xhci->op_regs->command);
+ temp |= (CMD_EIE);
+ xhci_dbg_trace(xhci, trace_xhci_dbg_init,
+ "// Enable interrupts, cmd = 0x%x.", temp);
+ writel(temp, &xhci->op_regs->command);
+
+ temp = readl(&xhci->ir_set->irq_pending);
+ xhci_dbg_trace(xhci, trace_xhci_dbg_init,
+ "// %s %p by writing 0x%x %s",
+ "Enabling event ring interrupter",
+ "to irq_pending", xhci->ir_set,
+ (unsigned int) ER_IRQ_ENABLE(temp));
+ writel(ER_IRQ_ENABLE(temp), &xhci->ir_set->irq_pending);
if (xhci_start(xhci)) {
xhci_halt(xhci);
+ spin_unlock_irqrestore(&xhci->lock, flags);
return -ENODEV;
}
xhci->cmd_ring_state = CMD_RING_STATE_RUNNING;
if (xhci->quirks & XHCI_NEC_HOST)
xhci_ring_cmd_db(xhci);
-
+ spin_unlock_irqrestore(&xhci->lock, flags);
return 0;
}
@@ -668,19 +693,6 @@ int xhci_run(struct usb_hcd *hcd)
temp |= (xhci->imod_interval / 250) & ER_IRQ_INTERVAL_MASK;
writel(temp, &xhci->ir_set->irq_control);
- /* Set the HCD state before we enable the irqs */
- temp = readl(&xhci->op_regs->command);
- temp |= (CMD_EIE);
- xhci_dbg_trace(xhci, trace_xhci_dbg_init,
- "// Enable interrupts, cmd = 0x%x.", temp);
- writel(temp, &xhci->op_regs->command);
-
- temp = readl(&xhci->ir_set->irq_pending);
- xhci_dbg_trace(xhci, trace_xhci_dbg_init,
- "// Enabling event ring interrupter %p by writing 0x%x to irq_pending",
- xhci->ir_set, (unsigned int) ER_IRQ_ENABLE(temp));
- writel(ER_IRQ_ENABLE(temp), &xhci->ir_set->irq_pending);
-
if (xhci->quirks & XHCI_NEC_HOST) {
struct xhci_command *command;
--
2.25.1
