This is a note to let you know that I've just added the patch titled
usb-core: Add LINEAR_FRAME_INTR_BINTERVAL USB quirk
to my usb git tree which can be found at
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git
in the usb-linus branch.
The patch will show up in the next release of the linux-next tree
(usually sometime within the next 24 hours during the week.)
The patch will hopefully also be merged in Linus's tree for the
next -rc kernel release.
If you have any questions about this process, please let me know.
>From 3243367b209faed5c320a4e5f9a565ee2a2ba958 Mon Sep 17 00:00:00 2001
From: Samuel Thibault <samuel.thibault@xxxxxxxxxxxx>
Date: Mon, 13 Mar 2017 20:50:08 +0100
Subject: 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@xxxxxxxxxxxx>
Acked-by: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>
Cc: stable <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/usb/core/config.c | 10 ++++++++++
drivers/usb/core/quirks.c | 8 ++++++++
include/linux/usb/quirks.h | 6 ++++++
3 files changed, 24 insertions(+)
diff --git a/drivers/usb/core/config.c b/drivers/usb/core/config.c
index 25dbd8c7aec7..4be52c602e9b 100644
--- 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 24f9f98968a5..96b21b0dac1e 100644
--- 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 1d0043dc34e4..de2a722fe3cf 100644
--- 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 */
--
2.12.0