diff options
| author | Bjørn Mork <bjorn@mork.no> | 2012-01-20 04:49:57 +0400 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2012-01-25 02:43:13 +0400 |
| commit | 7e3054a005537f28544ab2870c375458362f7473 (patch) | |
| tree | 39e3b0522fe85b28f5cd80dce52139c7639e1525 | |
| parent | 8143a8963c374116f84aba15dcaeaf02370c8098 (diff) | |
| download | linux-7e3054a005537f28544ab2870c375458362f7473.tar.xz | |
USB: cdc-wdm: Avoid hanging on interface with no USB_CDC_DMM_TYPE
The probe does not strictly require the USB_CDC_DMM_TYPE
descriptor, which is a good thing as it makes the driver
usable on non-conforming interfaces. A user could e.g.
bind to it to a CDC ECM interface by using the new_id and
bind sysfs files. But this would fail with a 0 buffer length
due to the missing descriptor.
Fix by defining a reasonable fallback size: The minimum
device receive buffer size required by the CDC WMC standard,
revision 1.1
Signed-off-by: Bjørn Mork <bjorn@mork.no>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
| -rw-r--r-- | drivers/usb/class/cdc-wdm.c | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/drivers/usb/class/cdc-wdm.c b/drivers/usb/class/cdc-wdm.c index bb8208a13a53..c0197af22fd8 100644 --- a/drivers/usb/class/cdc-wdm.c +++ b/drivers/usb/class/cdc-wdm.c @@ -57,6 +57,8 @@ MODULE_DEVICE_TABLE (usb, wdm_ids); #define WDM_MAX 16 +/* CDC-WMC r1.1 requires wMaxCommand to be "at least 256 decimal (0x100)" */ +#define WDM_DEFAULT_BUFSIZE 256 static DEFINE_MUTEX(wdm_mutex); @@ -602,7 +604,7 @@ static int wdm_probe(struct usb_interface *intf, const struct usb_device_id *id) struct usb_cdc_dmm_desc *dmhd; u8 *buffer = intf->altsetting->extra; int buflen = intf->altsetting->extralen; - u16 maxcom = 0; + u16 maxcom = WDM_DEFAULT_BUFSIZE; if (!buffer) goto out; |