This is a note to let you know that I've just added the patch titled
USB: serial drivers need to use larger bulk-in buffers
to my usb git tree which can be found at
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb-2.6.git
in the usb-next 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 also will be merged in the next major kernel release
during the merge window.
If you have any questions about this process, please let me know.
>From 969e3033ae7733a0af8f7742ca74cd16c0857e71 Mon Sep 17 00:00:00 2001
From: Alan Stern <[email protected]>
Date: Wed, 23 Feb 2011 15:28:18 -0500
Subject: USB: serial drivers need to use larger bulk-in buffers
When a driver doesn't know how much data a device is going to send,
the buffer size should be at least as big as the endpoint's maxpacket
value. The serial drivers don't follow this rule; many of them
request only 256-byte bulk-in buffers. As a result, they suffer
overflow errors if a high-speed device wants to send a lot of data,
because high-speed bulk endpoints are required to have a maxpacket
size of 512.
This patch (as1450) fixes the problem by using the driver's
bulk_in_size value as a minimum, always allocating buffers no smaller
than the endpoint's maxpacket size.
Signed-off-by: Alan Stern <[email protected]>
Tested-by: Flynn Marquardt <[email protected]>
CC: <[email protected]> [after .39-rc1 is out]
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
drivers/usb/serial/usb-serial.c | 5 ++---
include/linux/usb/serial.h | 3 ++-
2 files changed, 4 insertions(+), 4 deletions(-)
diff --git a/drivers/usb/serial/usb-serial.c b/drivers/usb/serial/usb-serial.c
index 546a521..2ff90a9 100644
--- a/drivers/usb/serial/usb-serial.c
+++ b/drivers/usb/serial/usb-serial.c
@@ -911,9 +911,8 @@ int usb_serial_probe(struct usb_interface *interface,
dev_err(&interface->dev, "No free urbs available\n");
goto probe_error;
}
- buffer_size = serial->type->bulk_in_size;
- if (!buffer_size)
- buffer_size = le16_to_cpu(endpoint->wMaxPacketSize);
+ buffer_size = max_t(int, serial->type->bulk_in_size,
+ le16_to_cpu(endpoint->wMaxPacketSize));
port->bulk_in_size = buffer_size;
port->bulk_in_endpointAddress = endpoint->bEndpointAddress;
port->bulk_in_buffer = kmalloc(buffer_size, GFP_KERNEL);
diff --git a/include/linux/usb/serial.h b/include/linux/usb/serial.h
index c904913..45f3b9d 100644
--- a/include/linux/usb/serial.h
+++ b/include/linux/usb/serial.h
@@ -191,7 +191,8 @@ static inline void usb_set_serial_data(struct usb_serial
*serial, void *data)
* @id_table: pointer to a list of usb_device_id structures that define all
* of the devices this structure can support.
* @num_ports: the number of different ports this device will have.
- * @bulk_in_size: bytes to allocate for bulk-in buffer (0 = end-point size)
+ * @bulk_in_size: minimum number of bytes to allocate for bulk-in buffer
+ * (0 = end-point size)
* @bulk_out_size: bytes to allocate for bulk-out buffer (0 = end-point size)
* @calc_num_ports: pointer to a function to determine how many ports this
* device has dynamically. It will be called after the probe()
--
1.7.3.2
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