This patch adds a usb quirk to support devices with bInterval values
expressed as microframes. The quirk causes the parse endpoint function
to modify the reported bInterval to a standards conforming value.
There is currently code in the endpoint parser that checks for
bIntervals that are outside of the valid range (1-16 for USB 2+).
In this case, the code assumes the bInterval is being reported in
1ms frames. As well, the correction is only applied if the original
bInterval value is out of the 1-16 range.
With this quirk applied to the device, the bInterval will be
accurately adjusted from microframes to an exponent.
Signed-off-by: James P Michels III <james.p.michels@xxxxxxxxx>
---
drivers/usb/core/config.c | 9 +++++++++
drivers/usb/core/quirks.c | 4 ++++
include/linux/usb/quirks.h | 9 +++++++++
3 files changed, 22 insertions(+)
diff --git a/drivers/usb/core/config.c b/drivers/usb/core/config.c
index 1ab4df1..191ce69 100644
--- a/drivers/usb/core/config.c
+++ b/drivers/usb/core/config.c
@@ -199,6 +199,15 @@ static int usb_parse_endpoint(struct device *ddev, int cfgno, int inum,
if (n == 0)
n = 9; /* 32 ms = 2^(9-1) uframes */
j = 16;
+
+ /* Adjust bInterval for quirked devices.
+ * This quirk fixes bIntervals reported in
+ * linear microframes. */
+ if (to_usb_device(ddev)->quirks &
+ USB_QUIRK_LINEAR_UFRAME_INTR_BINTERVAL) {
+ n = clamp(fls(d->bInterval), i, j);
+ i = j = n;
+ }
break;
default: /* USB_SPEED_FULL or _LOW */
/* For low-speed, 10 ms is the official minimum.
diff --git a/drivers/usb/core/quirks.c b/drivers/usb/core/quirks.c
index 739ee8e..33c42de 100644
--- a/drivers/usb/core/quirks.c
+++ b/drivers/usb/core/quirks.c
@@ -145,6 +145,10 @@ static const struct usb_device_id usb_quirk_list[] = {
/* SKYMEDI USB_DRIVE */
{ USB_DEVICE(0x1516, 0x8628), .driver_info = USB_QUIRK_RESET_RESUME },
+ /* Razer - Razer Blade Keyboard */
+ { USB_DEVICE(0x1532, 0x0116), .driver_info =
+ USB_QUIRK_LINEAR_UFRAME_INTR_BINTERVAL },
+
/* BUILDWIN Photo Frame */
{ USB_DEVICE(0x1908, 0x1315), .driver_info =
USB_QUIRK_HONOR_BNUMINTERFACES },
diff --git a/include/linux/usb/quirks.h b/include/linux/usb/quirks.h
index 52f944d..9219995 100644
--- a/include/linux/usb/quirks.h
+++ b/include/linux/usb/quirks.h
@@ -30,4 +30,13 @@
descriptor */
#define USB_QUIRK_DELAY_INIT 0x00000040
+/* The USB 2.0 and USB 3.0 spec require the interval in microframes
+ (1 microframe = 125 microseconds) to be calculated as
+ interval = 2 ^ (bInterval -1).
+
+ Devices with this quirk report their bInterval as the result of
+ this calculation instead of the exponent variable used in the
+ calculation */
+#define USB_QUIRK_LINEAR_UFRAME_INTR_BINTERVAL 0x00000080
+
#endif /* __LINUX_USB_QUIRKS_H */
--
1.9.1
--
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