Hello.
Sorry for the grammar nitpicking but since it's in the comments, I felt
the necessity to comment.
On 12/4/2015 5:40 AM, Chunfeng Yun wrote:
when ip fail to enter sleep mode, register access protection will
Fails.
be disabed, at the same time if all clocks are disabled, access
^^^^^^^ disabled
register will hang up AHB bus.
the common case causes ip sleep fail is that after all ports enter
Failure.
U3 but before ip enters sleep mode, a port receives a resume
signal('K'). this will happens when such as clicks mouse to try to
do remote wakeup to stop system enter suspend.
Wake up.
so stop polling roothubs to avoid access xHCI register on bus
Root hubs. Accessing.
suspend, and restart it when bus resume.
Resumes. Or "is resumed", maybe?
Signed-off-by: Chunfeng Yun <chunfeng.yun@xxxxxxxxxxxx>
---
drivers/usb/host/xhci-mtk.c | 23 +++++++++++++++++++++++
1 file changed, 23 insertions(+)
diff --git a/drivers/usb/host/xhci-mtk.c b/drivers/usb/host/xhci-mtk.c
index c9ab6a4..38635fb 100644
--- a/drivers/usb/host/xhci-mtk.c
+++ b/drivers/usb/host/xhci-mtk.c
@@ -696,9 +696,24 @@ static int xhci_mtk_remove(struct platform_device *dev)
}
#ifdef CONFIG_PM_SLEEP
+/*
+ * if ip sleep fail, and all clocks are disabled, access register will hang
Fails.
+ * AHB bus, so stop poll roothubs to avoid regs access on bus suspend.
Polling.
+ * and no need to check whether ip sleep fail or not; this will cause SPM to
Failed.
+ * wakeup system immediately after system suspend complete if ip sleep
Wake up.
+ * fail, it is what we wanted.
Fails.
+ */
[...]
MBR, Sergei
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