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path: root/drivers/input
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-rw-r--r--drivers/input/touchscreen/usbtouchscreen.c22
1 files changed, 18 insertions, 4 deletions
diff --git a/drivers/input/touchscreen/usbtouchscreen.c b/drivers/input/touchscreen/usbtouchscreen.c
index ae4b6b903629..5f87bed05467 100644
--- a/drivers/input/touchscreen/usbtouchscreen.c
+++ b/drivers/input/touchscreen/usbtouchscreen.c
@@ -106,6 +106,7 @@ struct usbtouch_device_info {
struct usbtouch_usb {
unsigned char *data;
dma_addr_t data_dma;
+ int data_size;
unsigned char *buffer;
int buf_len;
struct urb *irq;
@@ -1521,7 +1522,7 @@ static int usbtouch_reset_resume(struct usb_interface *intf)
static void usbtouch_free_buffers(struct usb_device *udev,
struct usbtouch_usb *usbtouch)
{
- usb_free_coherent(udev, usbtouch->type->rept_size,
+ usb_free_coherent(udev, usbtouch->data_size,
usbtouch->data, usbtouch->data_dma);
kfree(usbtouch->buffer);
}
@@ -1566,7 +1567,20 @@ static int usbtouch_probe(struct usb_interface *intf,
if (!type->process_pkt)
type->process_pkt = usbtouch_process_pkt;
- usbtouch->data = usb_alloc_coherent(udev, type->rept_size,
+ usbtouch->data_size = type->rept_size;
+ if (type->get_pkt_len) {
+ /*
+ * When dealing with variable-length packets we should
+ * not request more than wMaxPacketSize bytes at once
+ * as we do not know if there is more data coming or
+ * we filled exactly wMaxPacketSize bytes and there is
+ * nothing else.
+ */
+ usbtouch->data_size = min(usbtouch->data_size,
+ usb_endpoint_maxp(endpoint));
+ }
+
+ usbtouch->data = usb_alloc_coherent(udev, usbtouch->data_size,
GFP_KERNEL, &usbtouch->data_dma);
if (!usbtouch->data)
goto out_free;
@@ -1626,12 +1640,12 @@ static int usbtouch_probe(struct usb_interface *intf,
if (usb_endpoint_type(endpoint) == USB_ENDPOINT_XFER_INT)
usb_fill_int_urb(usbtouch->irq, udev,
usb_rcvintpipe(udev, endpoint->bEndpointAddress),
- usbtouch->data, type->rept_size,
+ usbtouch->data, usbtouch->data_size,
usbtouch_irq, usbtouch, endpoint->bInterval);
else
usb_fill_bulk_urb(usbtouch->irq, udev,
usb_rcvbulkpipe(udev, endpoint->bEndpointAddress),
- usbtouch->data, type->rept_size,
+ usbtouch->data, usbtouch->data_size,
usbtouch_irq, usbtouch);
usbtouch->irq->dev = udev;