Greg:
The UHCI controller in my laptop takes longer to turn off the
Resume-Detect bit than the 4 us allowed by uhci-hcd. Presumably other
computers will have the same problem.
This patch (as752) increases the maximum delay to 10 us, which should be
plenty, and uses polling to avoid penalizing systems which can turn the
bit off more quickly.
Alan Stern
Signed-off-by: Alan Stern <[EMAIL PROTECTED]>
---
Index: usb-2.6/drivers/usb/host/uhci-hub.c
===================================================================
--- usb-2.6.orig/drivers/usb/host/uhci-hub.c
+++ usb-2.6/drivers/usb/host/uhci-hub.c
@@ -84,6 +84,7 @@ static void uhci_finish_suspend(struct u
unsigned long port_addr)
{
int status;
+ int i;
if (inw(port_addr) & (USBPORTSC_SUSP | USBPORTSC_RD)) {
CLR_RH_PORTSTAT(USBPORTSC_SUSP | USBPORTSC_RD);
@@ -92,9 +93,14 @@ static void uhci_finish_suspend(struct u
/* The controller won't actually turn off the RD bit until
* it has had a chance to send a low-speed EOP sequence,
- * which takes 3 bit times (= 2 microseconds). We'll delay
- * slightly longer for good luck. */
- udelay(4);
+ * which is supposed to take 3 bit times (= 2 microseconds).
+ * Experiments show that some controllers take longer, so
+ * we'll poll for completion. */
+ for (i = 0; i < 10; ++i) {
+ if (!(inw(port_addr) & USBPORTSC_RD))
+ break;
+ udelay(1);
+ }
}
clear_bit(port, &uhci->resuming_ports);
}
-------------------------------------------------------------------------
Using Tomcat but need to do more? Need to support web services, security?
Get stuff done quickly with pre-integrated technology to make your job easier
Download IBM WebSphere Application Server v.1.0.1 based on Apache Geronimo
http://sel.as-us.falkag.net/sel?cmd=lnk&kid=120709&bid=263057&dat=121642
_______________________________________________
linux-usb-devel@lists.sourceforge.net
To unsubscribe, use the last form field at:
https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
