Re: BisonCam 5986:0203 kills USB

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Am Montag 23 November 2009 10:20:46 schrieb Oliver Neukum:
> Am Samstag, 21. November 2009 17:56:30 schrieb Alan Stern:
> this version should be efficient.
> Stephan, please test.

I have increased the delay to 1000us, as discussed and added a
tested-by notice.

Is my back-port of interest to anyone?

Cheers,
  Stephan
--
commit 1d272fa5ec701b8e39ed9e822f25a4c12f50aa71
Author: Oliver Neukum <oliver@xxxxxxxxxx>
Date:   Mon Nov 23 10:12:55 2009 +0100

    usb:workaround for EHCI with broken periodic schedules
    
    Some controllers must execute a periodic schedule for
    a minimum time before they can disable it.
    This adds a variable delay based on the time of the
    last enablement.

    Tested-by: stephan.diestelhorst@xxxxxxxxx

diff --git a/drivers/usb/host/ehci-hcd.c b/drivers/usb/host/ehci-hcd.c
index 9835e07..f5f5601 100644
--- a/drivers/usb/host/ehci-hcd.c
+++ b/drivers/usb/host/ehci-hcd.c
@@ -28,6 +28,7 @@
 #include <linux/errno.h>
 #include <linux/init.h>
 #include <linux/timer.h>
+#include <linux/ktime.h>
 #include <linux/list.h>
 #include <linux/interrupt.h>
 #include <linux/usb.h>
@@ -676,6 +677,7 @@ static int ehci_run (struct usb_hcd *hcd)
 	ehci_readl(ehci, &ehci->regs->command);	/* unblock posted writes */
 	msleep(5);
 	up_write(&ehci_cf_port_reset_rwsem);
+	ehci->last_periodic_enable = ktime_get_real();
 
 	temp = HC_VERSION(ehci_readl(ehci, &ehci->caps->hc_capbase));
 	ehci_info (ehci,
diff --git a/drivers/usb/host/ehci-pci.c b/drivers/usb/host/ehci-pci.c
index 378861b..ead5f4f 100644
--- a/drivers/usb/host/ehci-pci.c
+++ b/drivers/usb/host/ehci-pci.c
@@ -111,6 +111,10 @@ static int ehci_pci_setup(struct usb_hcd *hcd)
 	switch (pdev->vendor) {
 	case PCI_VENDOR_ID_INTEL:
 		ehci->need_io_watchdog = 0;
+		if (pdev->device == 0x27cc) {
+			ehci->broken_periodic = 1;
+			ehci_info(ehci, "using broken periodic workaround\n");
+		}
 		break;
 	case PCI_VENDOR_ID_TDI:
 		if (pdev->device == PCI_DEVICE_ID_TDI_EHCI) {
diff --git a/drivers/usb/host/ehci-sched.c b/drivers/usb/host/ehci-sched.c
index b25cdea..0468e88 100644
--- a/drivers/usb/host/ehci-sched.c
+++ b/drivers/usb/host/ehci-sched.c
@@ -475,6 +475,8 @@ static int enable_periodic (struct ehci_hcd *ehci)
 	/* make sure ehci_work scans these */
 	ehci->next_uframe = ehci_readl(ehci, &ehci->regs->frame_index)
 		% (ehci->periodic_size << 3);
+	if (unlikely(ehci->broken_periodic))
+		ehci->last_periodic_enable = ktime_get_real();
 	return 0;
 }
 
@@ -486,6 +488,15 @@ static int disable_periodic (struct ehci_hcd *ehci)
 	if (--ehci->periodic_sched)
 		return 0;
 
+	if (unlikely(ehci->broken_periodic)) {
+		ktime_t safe = ktime_add_us(ehci->last_periodic_enable, 1000);
+		ktime_t now = ktime_get_real();
+		s64 delay = ktime_us_delta(safe, now);
+		
+		if (unlikely(delay > 0))
+			udelay(delay);
+	}
+
 	/* did setting PSE not take effect yet?
 	 * takes effect only at frame boundaries...
 	 */
diff --git a/drivers/usb/host/ehci.h b/drivers/usb/host/ehci.h
index 064e768..2d85e21 100644
--- a/drivers/usb/host/ehci.h
+++ b/drivers/usb/host/ehci.h
@@ -118,6 +118,7 @@ struct ehci_hcd {			/* one per controller */
 	unsigned		stamp;
 	unsigned		random_frame;
 	unsigned long		next_statechange;
+	ktime_t			last_periodic_enable;
 	u32			command;
 
 	/* SILICON QUIRKS */
@@ -127,6 +128,7 @@ struct ehci_hcd {			/* one per controller */
 	unsigned		big_endian_desc:1;
 	unsigned		has_amcc_usb23:1;
 	unsigned		need_io_watchdog:1;
+	unsigned		broken_periodic:1;
 
 	/* required for usb32 quirk */
 	#define OHCI_CTRL_HCFS          (3 << 6)





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