[kernel] r10738 - in dists/trunk/linux-2.6/debian/patches: bugfix/all series
Gordon Farquharson
gordon-guest at alioth.debian.org
Fri Mar 7 04:07:38 UTC 2008
Author: gordon-guest
Date: Fri Mar 7 04:07:37 2008
New Revision: 10738
Log:
Add patch to fix WARNING: at drivers/usb/host/ehci-hcd.c:287 (see
http://lkml.org/lkml/2008/3/4/634). These message occur frequenctly on
the Linksys NSLU2 with 2.6.25-rc3.
Added:
dists/trunk/linux-2.6/debian/patches/bugfix/all/fix-iaa-watchdog-warnings.patch
Modified:
dists/trunk/linux-2.6/debian/patches/series/1~experimental.1
Added: dists/trunk/linux-2.6/debian/patches/bugfix/all/fix-iaa-watchdog-warnings.patch
==============================================================================
--- (empty file)
+++ dists/trunk/linux-2.6/debian/patches/bugfix/all/fix-iaa-watchdog-warnings.patch Fri Mar 7 04:07:37 2008
@@ -0,0 +1,126 @@
+The recent EHCI driver update to split the IAA watchdog timer out from
+the other timers made several things work better, but not everything;
+and it created a couple new issues in bugzilla. Ergo this patch:
+
+ - Handle a should-be-rare SMP race between the watchdog firing
+ and (very late) IAA interrupts;
+
+ - Remove a shouldn't-have-been-added WARN_ON() test;
+
+ - Guard against one observed OOPS;
+
+ - If this watchdog fires during clean HC shutdown, it should act
+ as a NOP instead of interfering with the shutdown sequence;
+
+ - Guard against silicon errata hypothesized by some vendors:
+ * IAA status latch broken, but IAAD cleared OK;
+ * IAAD wasn't cleared when IAA status got reported;
+
+The WARN_ON is in bugzilla as 10168; the OOPS as 10078.
+
+Signed-off-by: David Brownell <dbrownell at users.sourceforge.net>
+---
+ drivers/usb/host/ehci-hcd.c | 60 +++++++++++++++++++++++++++++++++-----------
+ 1 file changed, 45 insertions(+), 15 deletions(-)
+
+--- g26.orig/drivers/usb/host/ehci-hcd.c 2008-03-04 17:24:22.000000000 -0800
++++ g26/drivers/usb/host/ehci-hcd.c 2008-03-04 20:08:28.000000000 -0800
+@@ -257,23 +257,44 @@ static void ehci_iaa_watchdog(unsigned l
+ {
+ 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 = ehci_readl(ehci, &ehci->regs->status);
+- cmd = ehci_readl(ehci, &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 = ehci_readl(ehci, &ehci->regs->command);
++ if (cmd & CMD_IAAD)
++ ehci_writel(ehci, 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 = ehci_readl(ehci, &ehci->regs->status);
++ if ((status & STS_IAA) || !(cmd & CMD_IAAD)) {
+ COUNT (ehci->stats.lost_iaa);
+ ehci_writel(ehci, STS_IAA, &ehci->regs->status);
+ }
+- ehci_writel(ehci, cmd & ~CMD_IAAD, &ehci->regs->command);
++
++ ehci_vdbg(ehci, "IAA watchdog: status %x cmd %x\n",
++ status, cmd);
+ end_unlink_async(ehci);
+ }
+
+@@ -607,7 +628,7 @@ static int ehci_run (struct usb_hcd *hcd
+ static irqreturn_t ehci_irq (struct usb_hcd *hcd)
+ {
+ struct ehci_hcd *ehci = hcd_to_ehci (hcd);
+- u32 status, pcd_status = 0;
++ u32 status, pcd_status = 0, cmd;
+ int bh;
+
+ spin_lock (&ehci->lock);
+@@ -628,7 +649,7 @@ static irqreturn_t ehci_irq (struct usb_
+
+ /* clear (just) interrupts */
+ ehci_writel(ehci, status, &ehci->regs->status);
+- ehci_readl(ehci, &ehci->regs->command); /* unblock posted write */
++ cmd = ehci_readl(ehci, &ehci->regs->command);
+ bh = 0;
+
+ #ifdef VERBOSE_DEBUG
+@@ -649,8 +670,17 @@ static irqreturn_t ehci_irq (struct usb_
+
+ /* complete the unlinking of some qh [4.15.2.3] */
+ if (status & STS_IAA) {
+- COUNT (ehci->stats.reclaim);
+- end_unlink_async(ehci);
++ /* guard against (alleged) silicon errata */
++ if (cmd & CMD_IAAD) {
++ ehci_writel(ehci, 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);
++ } else
++ ehci_dbg(ehci, "IAA with nothing to reclaim?\n");
+ }
+
+ /* remote wakeup [4.3.1] */
+--
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Modified: dists/trunk/linux-2.6/debian/patches/series/1~experimental.1
==============================================================================
--- dists/trunk/linux-2.6/debian/patches/series/1~experimental.1 (original)
+++ dists/trunk/linux-2.6/debian/patches/series/1~experimental.1 Fri Mar 7 04:07:37 2008
@@ -35,3 +35,4 @@
+ bugfix/all/rtc-x1205-new-style-conversion.patch
+ bugfix/all/rtc-x1205-new-style-conversion-checkpatch-fixes.patch
+ bugfix/all/file2alias-cross-compile-fix.patch
++ bugfix/all/fix-iaa-watchdog-warnings.patch
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