2 files changed, 72 insertions, 27 deletions

diff --git a/drivers/usb/host/uhci-debug.c b/drivers/usb/host/uhci-debug.c
index e345f15b7d87..b40bc1ac9b8c 100644
--- a/drivers/usb/host/uhci-debug.c
+++ b/drivers/usb/host/uhci-debug.c
@@ -347,6 +347,7 @@ static int uhci_sprint_schedule(struct uhci_hcd *uhci, char *buf, int len)
         struct uhci_qh *qh;
         struct uhci_td *td;
         struct list_head *tmp, *head;
+        int nframes, nerrs;
 
         out += uhci_show_root_hub_state(uhci, out, len - (out - buf));
         out += sprintf(out, "HC status\n");
@@ -355,23 +356,60 @@ static int uhci_sprint_schedule(struct uhci_hcd *uhci, char *buf, int len)
                 return out - buf;
 
         out += sprintf(out, "Frame List\n");
+        nframes = 10;
+        nerrs = 0;
         for (i = 0; i < UHCI_NUMFRAMES; ++i) {
+                __le32 link, qh_dma;
+
+                j = 0;
                 td = uhci->frame_cpu[i];
+                link = uhci->frame[i];
                 if (!td)
-                        continue;
+                        goto check_link;
 
-                out += sprintf(out, "- Frame %d\n", i); \
-                if (td->dma_handle != (dma_addr_t)uhci->frame[i])
-                        out += sprintf(out, "    frame list does not match td->dma_handle!\n");
+                if (nframes > 0) {
+                        out += sprintf(out, "- Frame %d -> (%08x)\n",
+                                        i, le32_to_cpu(link));
+                        j = 1;
+                }
 
                 head = &td->fl_list;
                 tmp = head;
                 do {
                         td = list_entry(tmp, struct uhci_td, fl_list);
                         tmp = tmp->next;
-                        out += uhci_show_td(td, out, len - (out - buf), 4);
+                        if (cpu_to_le32(td->dma_handle) != link) {
+                                if (nframes > 0)
+                                        out += sprintf(out, "    link does "
+                                                "not match list entry!\n");
+                                else
+                                        ++nerrs;
+                        }
+                        if (nframes > 0)
+                                out += uhci_show_td(td, out,
+                                                len - (out - buf), 4);
+                        link = td->link;
                 } while (tmp != head);
+
+check_link:
+                qh_dma = uhci_frame_skel_link(uhci, i);
+                if (link != qh_dma) {
+                        if (nframes > 0) {
+                                if (!j) {
+                                        out += sprintf(out,
+                                                "- Frame %d -> (%08x)\n",
+                                                i, le32_to_cpu(link));
+                                        j = 1;
+                                }
+                                out += sprintf(out, "   link does not match "
+                                        "QH (%08x)!\n", le32_to_cpu(qh_dma));
+                        } else
+                                ++nerrs;
+                }
+                nframes -= j;
         }
+        if (nerrs > 0)
+                out += sprintf(out, "Skipped %d bad links\n", nerrs);
 
         out += sprintf(out, "Skeleton QHs\n");
 
diff --git a/drivers/usb/host/uhci-hcd.c b/drivers/usb/host/uhci-hcd.c
index e0d4c2358b39..49b9d390b95f 100644
--- a/drivers/usb/host/uhci-hcd.c
+++ b/drivers/usb/host/uhci-hcd.c
@@ -92,6 +92,34 @@ static void suspend_rh(struct uhci_hcd *uhci, enum uhci_rh_state new_state);
 static void wakeup_rh(struct uhci_hcd *uhci);
 static void uhci_get_current_frame_number(struct uhci_hcd *uhci);
 
+/*
+ * Calculate the link pointer DMA value for the first Skeleton QH in a frame.
+ */
+static __le32 uhci_frame_skel_link(struct uhci_hcd *uhci, int frame)
+{
+        int skelnum;
+
+        /*
+         * The interrupt queues will be interleaved as evenly as possible.
+         * There's not much to be done about period-1 interrupts; they have
+         * to occur in every frame.  But we can schedule period-2 interrupts
+         * in odd-numbered frames, period-4 interrupts in frames congruent
+         * to 2 (mod 4), and so on.  This way each frame only has two
+         * interrupt QHs, which will help spread out bandwidth utilization.
+         *
+         * ffs (Find First bit Set) does exactly what we need:
+         * 1,3,5,...  => ffs = 0 => use skel_int2_qh = skelqh[8],
+         * 2,6,10,... => ffs = 1 => use skel_int4_qh = skelqh[7], etc.
+         * ffs >= 7 => not on any high-period queue, so use
+         *      skel_int1_qh = skelqh[9].
+         * Add in UHCI_NUMFRAMES to insure at least one bit is set.
+         */
+        skelnum = 8 - (int) __ffs(frame | UHCI_NUMFRAMES);
+        if (skelnum <= 1)
+                skelnum = 9;
+        return UHCI_PTR_QH | cpu_to_le32(uhci->skelqh[skelnum]->dma_handle);
+}
+
 #include "uhci-debug.c"
 #include "uhci-q.c"
 #include "uhci-hub.c"
@@ -631,32 +659,11 @@ static int uhci_start(struct usb_hcd *hcd)
         /*
          * Fill the frame list: make all entries point to the proper
          * interrupt queue.
-         *
-         * The interrupt queues will be interleaved as evenly as possible.
-         * There's not much to be done about period-1 interrupts; they have
-         * to occur in every frame.  But we can schedule period-2 interrupts
-         * in odd-numbered frames, period-4 interrupts in frames congruent
-         * to 2 (mod 4), and so on.  This way each frame only has two
-         * interrupt QHs, which will help spread out bandwidth utilization.
          */
         for (i = 0; i < UHCI_NUMFRAMES; i++) {
-                int irq;
-
-                /*
-                 * ffs (Find First bit Set) does exactly what we need:
-                 * 1,3,5,...  => ffs = 0 => use skel_int2_qh = skelqh[8],
-                 * 2,6,10,... => ffs = 1 => use skel_int4_qh = skelqh[7], etc.
-                 * ffs >= 7 => not on any high-period queue, so use
-                 *      skel_int1_qh = skelqh[9].
-                 * Add UHCI_NUMFRAMES to insure at least one bit is set.
-                 */
-                irq = 8 - (int) __ffs(i + UHCI_NUMFRAMES);
-                if (irq <= 1)
-                        irq = 9;
 
                 /* Only place we don't use the frame list routines */
-                uhci->frame[i] = UHCI_PTR_QH |
-                                cpu_to_le32(uhci->skelqh[irq]->dma_handle);
+                uhci->frame[i] = uhci_frame_skel_link(uhci, i);
         }
 
         /*