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path: root/drivers/usb/core/config.c
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Diffstat (limited to 'drivers/usb/core/config.c')
-rw-r--r--drivers/usb/core/config.c28
1 files changed, 17 insertions, 11 deletions
diff --git a/drivers/usb/core/config.c b/drivers/usb/core/config.c
index 15ce4ab11688..a2d90aca779f 100644
--- a/drivers/usb/core/config.c
+++ b/drivers/usb/core/config.c
@@ -240,8 +240,10 @@ static int usb_parse_endpoint(struct device *ddev, int cfgno, int inum,
memcpy(&endpoint->desc, d, n);
INIT_LIST_HEAD(&endpoint->urb_list);
- /* Fix up bInterval values outside the legal range. Use 32 ms if no
- * proper value can be guessed. */
+ /*
+ * Fix up bInterval values outside the legal range.
+ * Use 10 or 8 ms if no proper value can be guessed.
+ */
i = 0; /* i = min, j = max, n = default */
j = 255;
if (usb_endpoint_xfer_int(d)) {
@@ -250,13 +252,15 @@ static int usb_parse_endpoint(struct device *ddev, int cfgno, int inum,
case USB_SPEED_SUPER_PLUS:
case USB_SPEED_SUPER:
case USB_SPEED_HIGH:
- /* Many device manufacturers are using full-speed
+ /*
+ * Many device manufacturers are using full-speed
* bInterval values in high-speed interrupt endpoint
- * descriptors. Try to fix those and fall back to a
- * 32 ms default value otherwise. */
+ * descriptors. Try to fix those and fall back to an
+ * 8-ms default value otherwise.
+ */
n = fls(d->bInterval*8);
if (n == 0)
- n = 9; /* 32 ms = 2^(9-1) uframes */
+ n = 7; /* 8 ms = 2^(7-1) uframes */
j = 16;
/*
@@ -271,10 +275,12 @@ static int usb_parse_endpoint(struct device *ddev, int cfgno, int inum,
}
break;
default: /* USB_SPEED_FULL or _LOW */
- /* For low-speed, 10 ms is the official minimum.
+ /*
+ * For low-speed, 10 ms is the official minimum.
* But some "overclocked" devices might want faster
- * polling so we'll allow it. */
- n = 32;
+ * polling so we'll allow it.
+ */
+ n = 10;
break;
}
} else if (usb_endpoint_xfer_isoc(d)) {
@@ -282,10 +288,10 @@ static int usb_parse_endpoint(struct device *ddev, int cfgno, int inum,
j = 16;
switch (to_usb_device(ddev)->speed) {
case USB_SPEED_HIGH:
- n = 9; /* 32 ms = 2^(9-1) uframes */
+ n = 7; /* 8 ms = 2^(7-1) uframes */
break;
default: /* USB_SPEED_FULL */
- n = 6; /* 32 ms = 2^(6-1) frames */
+ n = 4; /* 8 ms = 2^(4-1) frames */
break;
}
}