diff options
| -rw-r--r-- | drivers/usb/core/config.c | 28 |
1 files changed, 17 insertions, 11 deletions
diff --git a/drivers/usb/core/config.c b/drivers/usb/core/config.c index 894894f2ff93..81336acc7040 100644 --- a/drivers/usb/core/config.c +++ b/drivers/usb/core/config.c @@ -184,8 +184,10 @@ 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)) { @@ -193,13 +195,15 @@ static int usb_parse_endpoint(struct device *ddev, int cfgno, int inum, switch (to_usb_device(ddev)->speed) { 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; /* @@ -214,10 +218,12 @@ 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)) { @@ -225,10 +231,10 @@ 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; } } |