[PATCH] UHCI: Reimplement FSBR

This patch (as683) re-implements Full-Speed Bandwidth Reclamation (FSBR)
properly.  It keeps track of which endpoint queues have advanced, and
when none have advanced for a sufficiently long time, FSBR is turned
off.  The next TD on each of the non-moving queues is modified to
generate an interrupt on completion, so that FSBR can be re-enabled as
soon as the hardware starts to make some progress.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 12 insertions, 3 deletions

diff --git a/drivers/usb/host/uhci-hcd.h b/drivers/usb/host/uhci-hcd.h
index 90ef7fbbf2fb..04938e64799f 100644
--- a/drivers/usb/host/uhci-hcd.h
+++ b/drivers/usb/host/uhci-hcd.h
@@ -84,6 +84,13 @@
 #define CAN_SCHEDULE_FRAMES     1000    /* how far in the future frames
                                          * can be scheduled */
 
+/* When no queues need Full-Speed Bandwidth Reclamation,
+ * delay this long before turning FSBR off */
+#define FSBR_OFF_DELAY          msecs_to_jiffies(400)
+
+/* If a queue hasn't advanced after this much time, assume it is stuck */
+#define QH_WAIT_TIMEOUT         msecs_to_jiffies(200)
+
 
 /*
  *      Queue Headers
@@ -131,6 +138,7 @@ struct uhci_qh {
         struct uhci_td *dummy_td;       /* Dummy TD to end the queue */
         struct uhci_td *post_td;        /* Last TD completed */
 
+        unsigned long advance_jiffies;  /* Time of last queue advance */
         unsigned int unlink_frame;      /* When the QH was unlinked */
         int state;                      /* QH_STATE_xxx; see above */
         int type;                       /* Queue type (control, bulk, etc) */
@@ -138,6 +146,7 @@ struct uhci_qh {
         unsigned int initial_toggle:1;  /* Endpoint's current toggle value */
         unsigned int needs_fixup:1;     /* Must fix the TD toggle values */
         unsigned int is_stopped:1;      /* Queue was stopped by error/unlink */
+        unsigned int wait_expired:1;    /* QH_WAIT_TIMEOUT has expired */
 } __attribute__((aligned(16)));
 
 /*
@@ -397,8 +406,7 @@ struct uhci_hcd {
         __le32 *frame;
         void **frame_cpu;               /* CPU's frame list */
 
-        int fsbr;                       /* Full-speed bandwidth reclamation */
-        unsigned long fsbrtimeout;      /* FSBR delay */
+        unsigned long fsbr_jiffies;     /* Time when FSBR was last wanted */
 
         enum uhci_rh_state rh_state;
         unsigned long auto_stop_time;           /* When to AUTO_STOP */
@@ -413,6 +421,7 @@ struct uhci_hcd {
         unsigned int working_RD:1;              /* Suspended root hub doesn't
                                                    need to be polled */
         unsigned int is_initialized:1;          /* Data structure is usable */
+        unsigned int fsbr_is_on:1;              /* FSBR is turned on */
 
         /* Support for port suspend/resume/reset */
         unsigned long port_c_suspend;           /* Bit-arrays of ports */
@@ -451,7 +460,7 @@ struct urb_priv {
         struct uhci_qh *qh;             /* QH for this URB */
         struct list_head td_list;
 
-        unsigned fsbr : 1;              /* URB turned on FSBR */
+        unsigned fsbr:1;                /* URB wants FSBR */
 };