Commit 7dedacf4 authored by David Brownell's avatar David Brownell Committed by Linus Torvalds
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[PATCH] USB: ehci: microframe handling fix 



This patch has a one line oops fix, plus related cleanups.

 - The bugfix uses microframe scheduling data given to the hardware to
   test "is this a periodic QH", rather than testing for nonzero period.
   (Prevents an oops by providing the correct answer.)

 - The cleanup going along with the patch should make it clearer what's
   going on whenever those bitfields are accessed.

The bug came about when, around January, two new kinds of EHCI interrupt
scheduling operation were added, involving both the high speed (24 KBytes
per millisec) and low/full speed (1-64 bytes per millisec) microframe
scheduling.  A driver for the Edirol UA-1000 Audio Capture Unit ran into
the oops; it used one of the newly supported high speed modes.

Signed-off-by: default avatarDavid Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 003ba515

drivers/usb/host/ehci-dbg.c

+1 −1
Original line number Diff line number Diff line
@@ -527,7 +527,7 @@ show_periodic (struct class_device *class_dev, char *buf) 
						p.qh->period,

						le32_to_cpup (&p.qh->hw_info2)

							/* uframe masks */

							& 0xffff,

							& (QH_CMASK | QH_SMASK),

						p.qh);

				size -= temp;

				next += temp;

drivers/usb/host/ehci-q.c

+3 −2
Original line number Diff line number Diff line
@@ -222,7 +222,7 @@ __acquires(ehci->lock) 
		struct ehci_qh	*qh = (struct ehci_qh *) urb->hcpriv;



		/* S-mask in a QH means it's an interrupt urb */

		if ((qh->hw_info2 & __constant_cpu_to_le32 (0x00ff)) != 0) {

		if ((qh->hw_info2 & __constant_cpu_to_le32 (QH_SMASK)) != 0) {



			/* ... update hc-wide periodic stats (for usbfs) */

			ehci_to_hcd(ehci)->self.bandwidth_int_reqs--;
@@ -428,7 +428,8 @@ halt: 
			/* should be rare for periodic transfers,

			 * except maybe high bandwidth ...

			 */

			if (qh->period) {

			if ((__constant_cpu_to_le32 (QH_SMASK)

					& qh->hw_info2) != 0) {

				intr_deschedule (ehci, qh);

				(void) qh_schedule (ehci, qh);

			} else

drivers/usb/host/ehci-sched.c

+7 −6
Original line number Diff line number Diff line
@@ -301,7 +301,7 @@ static int qh_link_periodic (struct ehci_hcd *ehci, struct ehci_qh *qh) 


	dev_dbg (&qh->dev->dev,

		"link qh%d-%04x/%p start %d [%d/%d us]\n",

		period, le32_to_cpup (&qh->hw_info2) & 0xffff,

		period, le32_to_cpup (&qh->hw_info2) & (QH_CMASK | QH_SMASK),

		qh, qh->start, qh->usecs, qh->c_usecs);



	/* high bandwidth, or otherwise every microframe */
@@ -385,7 +385,8 @@ static void qh_unlink_periodic (struct ehci_hcd *ehci, struct ehci_qh *qh) 


	dev_dbg (&qh->dev->dev,

		"unlink qh%d-%04x/%p start %d [%d/%d us]\n",

		qh->period, le32_to_cpup (&qh->hw_info2) & 0xffff,

		qh->period,

		le32_to_cpup (&qh->hw_info2) & (QH_CMASK | QH_SMASK),

		qh, qh->start, qh->usecs, qh->c_usecs);



	/* qh->qh_next still "live" to HC */
@@ -411,7 +412,7 @@ static void intr_deschedule (struct ehci_hcd *ehci, struct ehci_qh *qh) 
	 * active high speed queues may need bigger delays...

	 */

	if (list_empty (&qh->qtd_list)

			|| (__constant_cpu_to_le32 (0x0ff << 8)

			|| (__constant_cpu_to_le32 (QH_CMASK)

					& qh->hw_info2) != 0)

		wait = 2;

	else
@@ -533,7 +534,7 @@ static int qh_schedule (struct ehci_hcd *ehci, struct ehci_qh *qh) 


	/* reuse the previous schedule slots, if we can */

	if (frame < qh->period) {

		uframe = ffs (le32_to_cpup (&qh->hw_info2) & 0x00ff);

		uframe = ffs (le32_to_cpup (&qh->hw_info2) & QH_SMASK);

		status = check_intr_schedule (ehci, frame, --uframe,

				qh, &c_mask);

	} else {
@@ -569,10 +570,10 @@ static int qh_schedule (struct ehci_hcd *ehci, struct ehci_qh *qh) 
		qh->start = frame;



		/* reset S-frame and (maybe) C-frame masks */

		qh->hw_info2 &= __constant_cpu_to_le32 (~0xffff);

		qh->hw_info2 &= __constant_cpu_to_le32(~(QH_CMASK | QH_SMASK));

		qh->hw_info2 |= qh->period

			? cpu_to_le32 (1 << uframe)

			: __constant_cpu_to_le32 (0xff);

			: __constant_cpu_to_le32 (QH_SMASK);

		qh->hw_info2 |= c_mask;

	} else

		ehci_dbg (ehci, "reused qh %p schedule\n", qh);

drivers/usb/host/ehci.h

+5 −0
Original line number Diff line number Diff line
@@ -385,6 +385,11 @@ struct ehci_qh { 
	__le32			hw_info1;        /* see EHCI 3.6.2 */

#define	QH_HEAD		0x00008000

	__le32			hw_info2;        /* see EHCI 3.6.2 */

#define	QH_SMASK	0x000000ff

#define	QH_CMASK	0x0000ff00

#define	QH_HUBADDR	0x007f0000

#define	QH_HUBPORT	0x3f800000

#define	QH_MULT		0xc0000000

	__le32			hw_current;	 /* qtd list - see EHCI 3.6.4 */

	

	/* qtd overlay (hardware parts of a struct ehci_qtd) */

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