Hi Guys:
I found a EHCI IC bug on Intel oaktrail platform. Here is my patch.
>From EHCI Spec p.28 HC should clear PORT_SUSPEND when SW clears
PORT_RESUME. In Intel Oaktrail platform, MPH (Multi-Port Host
Controller) core clears PORT_SUSPEND directly when SW sets PORT_RESUME
bit. If we rely on PORT_SUSPEND bit to stop USB resume, we will miss
the action of clearing PORT_RESUME. This will cause unexpected long
resume signal on USB bus.
---------------------------------------------------------------------------------------------------
From: Wang Zhi <zhi.wang@xxxxxxxxxxxxx>
Date: Thu, 04 Aug 2011 21:34:57 -0700
Subject: [PATCH]: USB: EHCI: Do not rely on PORT_SUSPEND to stop USB
resuming in ehci_bus_resume().
>From EHCI Spec p.28 HC should clear PORT_SUSPEND when SW clears
PORT_RESUME. In Intel Oaktrail platform, MPH (Multi-Port Host
Controller) core clears PORT_SUSPEND directly when SW sets PORT_RESUME
bit. If we rely on PORT_SUSPEND bit to stop USB resume, we will miss
the action of clearing PORT_RESUME. This will cause unexpected long
resume signal on USB bus.
Signed-off-by: Wang Zhi <zhi.wang@xxxxxxxxxxxxx>
---
/usr/local/bin/format-patch: line 34: diffstat: command not found
diff --git a/drivers/usb/host/ehci-hub.c b/drivers/usb/host/ehci-hub.c
index ea6184b..2f6cf9b 100644
--- a/drivers/usb/host/ehci-hub.c
+++ b/drivers/usb/host/ehci-hub.c
@@ -343,7 +343,7 @@ static int ehci_bus_resume (struct usb_hcd *hcd)
u32 temp;
u32 power_okay;
int i;
- u8 resume_needed = 0;
+ unsigned long resume_needed = 0;
if (time_before (jiffies, ehci->next_statechange))
msleep(5);
@@ -416,7 +416,7 @@ static int ehci_bus_resume (struct usb_hcd *hcd)
if (test_bit(i, &ehci->bus_suspended) &&
(temp & PORT_SUSPEND)) {
temp |= PORT_RESUME;
- resume_needed = 1;
+ set_bit(i, &resume_needed);
}
ehci_writel(ehci, temp, &ehci->regs->port_status [i]);
}
@@ -432,7 +432,7 @@ static int ehci_bus_resume (struct usb_hcd *hcd)
while (i--) {
temp = ehci_readl(ehci, &ehci->regs->port_status [i]);
if (test_bit(i, &ehci->bus_suspended) &&
- (temp & PORT_SUSPEND)) {
+ test_bit(i, &resume_needed)) {
temp &= ~(PORT_RWC_BITS | PORT_RESUME);
ehci_writel(ehci, temp, &ehci->regs->port_status [i]);
ehci_vdbg (ehci, "resumed port %d\n", i + 1);
--
To unsubscribe from this list: send the line "unsubscribe linux-usb" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
