Attachment 297010 Details for Bug 435670 – Another USB patch to make things better

[patch] Another USB patch to make things better

SBX00_USB_hang_fix_RHEL5.1_new.patch (text/plain), 3.43 KB, created by Shane Huang on 2008-03-06 08:42:51 UTC

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Creator: Shane Huang

Created: 2008-03-06 08:42:51 UTC

Size: 3.43 KB

patch

obsolete

>diff -ruN c/drivers/usb/host/ehci-hcd.c d/drivers/usb/host/ehci-hcd.c
>--- c/drivers/usb/host/ehci-hcd.c	2008-03-06 16:14:46.000000000 +0800
>+++ d/drivers/usb/host/ehci-hcd.c	2008-03-06 16:17:55.000000000 +0800
>@@ -268,23 +268,44 @@
> {
> 	struct ehci_hcd		*ehci = (struct ehci_hcd *) param;
> 	unsigned long		flags;
>-	u32			status, cmd;
> 
> 	spin_lock_irqsave (&ehci->lock, flags);
>-	WARN_ON(!ehci->reclaim);
>-
>-	status = readl(&ehci->regs->status);
>-	cmd = readl(&ehci->regs->command);
>-	ehci_dbg(ehci, "IAA watchdog: status %x cmd %x\n", status, cmd);
> 
>-	/* lost IAA irqs wedge things badly; seen first with a vt8235 */
>-	if (ehci->reclaim) {
>-		if (status & STS_IAA) {
>-			ehci_vdbg (ehci, "lost IAA\n");
>+	/* Lost IAA irqs wedge things badly; seen first with a vt8235.
>+	 * So we need this watchdog, but must protect it against both
>+	 * (a) SMP races against real IAA firing and retriggering, and
>+	 * (b) clean HC shutdown, when IAA watchdog was pending.
>+	 */
>+	if (ehci->reclaim
>+			&& !timer_pending(&ehci->iaa_watchdog)
>+			&& HC_IS_RUNNING(ehci_to_hcd(ehci)->state)) {
>+		u32 cmd, status;
>+
>+		/* If we get here, IAA is *REALLY* late.  It's barely
>+		 * conceivable that the system is so busy that CMD_IAAD
>+		 * is still legitimately set, so let's be sure it's
>+		 * clear before we read STS_IAA.  (The HC should clear
>+		 * CMD_IAAD when it sets STS_IAA.)
>+		 */
>+		cmd = readl(&ehci->regs->command);
>+		if (cmd & CMD_IAAD)
>+			writel(cmd & ~CMD_IAAD,
>+					&ehci->regs->command);
>+
>+		/* If IAA is set here it either legitimately triggered
>+		 * before we cleared IAAD above (but _way_ late, so we'll
>+		 * still count it as lost) ... or a silicon erratum:
>+		 * - VIA seems to set IAA without triggering the IRQ;
>+		 * - IAAD potentially cleared without setting IAA.
>+		 */
>+		status = readl(&ehci->regs->status);
>+		if ((status & STS_IAA) || !(cmd & CMD_IAAD)) {
> 			COUNT (ehci->stats.lost_iaa);
> 			writel (STS_IAA, &ehci->regs->status);
> 		}
>-		writel(cmd & ~CMD_IAAD, &ehci->regs->command);
>+
>+		ehci_vdbg(ehci, "IAA watchdog: status %x cmd %x\n",
>+				status, cmd);
> 		end_unlink_async(ehci, NULL);
> 	}
> 
>@@ -586,7 +607,7 @@
> static irqreturn_t ehci_irq (struct usb_hcd *hcd, struct pt_regs *regs)
> {
> 	struct ehci_hcd		*ehci = hcd_to_ehci (hcd);
>-	u32			status;
>+	u32			status, cmd;
> 	int			bh;
> 
> 	spin_lock (&ehci->lock);
>@@ -607,7 +628,7 @@
> 
> 	/* clear (just) interrupts */
> 	writel (status, &ehci->regs->status);
>-	readl (&ehci->regs->command);	/* unblock posted write */
>+	cmd = readl(&ehci->regs->command);
> 	bh = 0;
> 
> #ifdef	EHCI_VERBOSE_DEBUG
>@@ -628,8 +649,17 @@
> 
> 	/* complete the unlinking of some qh [4.15.2.3] */
> 	if (status & STS_IAA) {
>-		COUNT (ehci->stats.reclaim);
>-		end_unlink_async(ehci, NULL);
>+		/* guard against (alleged) silicon errata */
>+		if (cmd & CMD_IAAD) {
>+			writel(cmd & ~CMD_IAAD,
>+					&ehci->regs->command);
>+			ehci_dbg(ehci, "IAA with IAAD still set?\n");
>+		}
>+		if (ehci->reclaim) {
>+			COUNT(ehci->stats.reclaim);
>+			end_unlink_async(ehci, NULL);
>+		} else
>+			ehci_dbg(ehci, "IAA with nothing to reclaim?\n");
> 	}
> 
> 	/* remote wakeup [4.3.1] */
>diff -ruN c/drivers/usb/host/ehci-q.c d/drivers/usb/host/ehci-q.c
>--- c/drivers/usb/host/ehci-q.c	2008-03-06 16:14:40.000000000 +0800
>+++ d/drivers/usb/host/ehci-q.c	2008-03-06 16:17:48.000000000 +0800
>@@ -969,11 +969,6 @@
> 
> 	iaa_watchdog_done(ehci);
> 
>-	if (!qh) {
>-		WARN_ON(1);
>-		return;
>-	}
>-
> 	// qh->hw_next = cpu_to_le32 (qh->qh_dma);
> 	qh->qh_state = QH_STATE_IDLE;
> 	qh->qh_next.qh = NULL;

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Attachments on bug 435670: 296565 | 296703 | 297010