usb-core: Add LINEAR_FRAME_INTR_BINTERVAL USB quirk

Some USB 2.0 devices erroneously report millisecond values in
bInterval. The generic config code manages to catch most of them,
but in some cases it's not completely enough.

The case at stake here is a USB 2.0 braille device, which wants to
announce 10ms and thus sets bInterval to 10, but with the USB 2.0
computation that yields to 64ms.  It happens that one can type fast
enough to reach this interval and get the device buffers overflown,
leading to problematic latencies.  The generic config code does not
catch this case because the 64ms is considered a sane enough value.

This change thus adds a USB_QUIRK_LINEAR_FRAME_INTR_BINTERVAL quirk
to mark devices which actually report milliseconds in bInterval,
and marks Vario Ultra devices as needing it.

Signed-off-by: Samuel Thibault <samuel.thibault@ens-lyon.org>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/core/config.c b/drivers/usb/core/config.c
index 25dbd8c7aec73345d357c2a75ff0cde26c918217..4be52c602e9b7a7de6a76ecb4be686cb12ec9950 100644 (file)
--- a/drivers/usb/core/config.c
+++ b/drivers/usb/core/config.c
@@ -280,6 +280,16 @@ static int usb_parse_endpoint(struct device *ddev, int cfgno, int inum,
 
                        /*
                         * Adjust bInterval for quirked devices.
+                        */
+                       /*
+                        * This quirk fixes bIntervals reported in ms.
+                        */
+                       if (to_usb_device(ddev)->quirks &
+                               USB_QUIRK_LINEAR_FRAME_INTR_BINTERVAL) {
+                               n = clamp(fls(d->bInterval) + 3, i, j);
+                               i = j = n;
+                       }
+                       /*
                         * This quirk fixes bIntervals reported in
                         * linear microframes.
                         */

diff --git a/drivers/usb/core/quirks.c b/drivers/usb/core/quirks.c
index 24f9f98968a5d860f83920287a5b7deb4c98bed6..96b21b0dac1e8c15fb20c19c85d13a58ab95b285 100644 (file)
--- a/drivers/usb/core/quirks.c
+++ b/drivers/usb/core/quirks.c
@@ -170,6 +170,14 @@ static const struct usb_device_id usb_quirk_list[] = {
        /* M-Systems Flash Disk Pioneers */
        { USB_DEVICE(0x08ec, 0x1000), .driver_info = USB_QUIRK_RESET_RESUME },
 
+       /* Baum Vario Ultra */
+       { USB_DEVICE(0x0904, 0x6101), .driver_info =
+                       USB_QUIRK_LINEAR_FRAME_INTR_BINTERVAL },
+       { USB_DEVICE(0x0904, 0x6102), .driver_info =
+                       USB_QUIRK_LINEAR_FRAME_INTR_BINTERVAL },
+       { USB_DEVICE(0x0904, 0x6103), .driver_info =
+                       USB_QUIRK_LINEAR_FRAME_INTR_BINTERVAL },
+
        /* Keytouch QWERTY Panel keyboard */
        { USB_DEVICE(0x0926, 0x3333), .driver_info =
                        USB_QUIRK_CONFIG_INTF_STRINGS },

diff --git a/include/linux/usb/quirks.h b/include/linux/usb/quirks.h
index 1d0043dc34e427403a1c82458249bed83e87d3a0..de2a722fe3cf7c457352eb02548f0351a669ddf5 100644 (file)
--- a/include/linux/usb/quirks.h
+++ b/include/linux/usb/quirks.h
@@ -50,4 +50,10 @@
 /* device can't handle Link Power Management */
 #define USB_QUIRK_NO_LPM                       BIT(10)
 
+/*
+ * Device reports its bInterval as linear frames instead of the
+ * USB 2.0 calculation.
+ */
+#define USB_QUIRK_LINEAR_FRAME_INTR_BINTERVAL  BIT(11)
+
 #endif /* __LINUX_USB_QUIRKS_H */