From fd5054c169d29747a44b4e1419ff47f57ae82dbc Mon Sep 17 00:00:00 2001 From: Erik Slagter Date: Wed, 11 May 2011 12:06:55 +0200 Subject: [PATCH] USB: cdc_acm: Fix oops when Droids MuIn LCD is connected The Droids MuIn LCD operates like a serial remote terminal. Data received are displayed directly on the LCD. This patch fixes the kernel null pointer oops when it is plugged in. Add NO_DATA_INTERFACE quirk to tell the driver that "control" and "data" interfaces are not separated for this device, which prevents dereferencing a null pointer in the device probe code. Signed-off-by: Erik Slagter Signed-off-by: Maxin B. John Tested-by: Erik Slagter Cc: stable Signed-off-by: Greg Kroah-Hartman --- drivers/usb/class/cdc-acm.c | 13 +++++++++++-- drivers/usb/class/cdc-acm.h | 1 + 2 files changed, 12 insertions(+), 2 deletions(-) diff --git a/drivers/usb/class/cdc-acm.c b/drivers/usb/class/cdc-acm.c index 58754b508a0f..395a347f2ebb 100644 --- a/drivers/usb/class/cdc-acm.c +++ b/drivers/usb/class/cdc-acm.c @@ -853,7 +853,7 @@ static int acm_probe(struct usb_interface *intf, u8 ac_management_function = 0; u8 call_management_function = 0; int call_interface_num = -1; - int data_interface_num; + int data_interface_num = -1; unsigned long quirks; int num_rx_buf; int i; @@ -937,7 +937,11 @@ next_desc: if (!union_header) { if (call_interface_num > 0) { dev_dbg(&intf->dev, "No union descriptor, using call management descriptor\n"); - data_interface = usb_ifnum_to_if(usb_dev, (data_interface_num = call_interface_num)); + /* quirks for Droids MuIn LCD */ + if (quirks & NO_DATA_INTERFACE) + data_interface = usb_ifnum_to_if(usb_dev, 0); + else + data_interface = usb_ifnum_to_if(usb_dev, (data_interface_num = call_interface_num)); control_interface = intf; } else { if (intf->cur_altsetting->desc.bNumEndpoints != 3) { @@ -1535,6 +1539,11 @@ static const struct usb_device_id acm_ids[] = { .driver_info = NOT_A_MODEM, }, + /* Support for Droids MuIn LCD */ + { USB_DEVICE(0x04d8, 0x000b), + .driver_info = NO_DATA_INTERFACE, + }, + /* control interfaces without any protocol set */ { USB_INTERFACE_INFO(USB_CLASS_COMM, USB_CDC_SUBCLASS_ACM, USB_CDC_PROTO_NONE) }, diff --git a/drivers/usb/class/cdc-acm.h b/drivers/usb/class/cdc-acm.h index 7b5c0bd07f80..ca7937f26e27 100644 --- a/drivers/usb/class/cdc-acm.h +++ b/drivers/usb/class/cdc-acm.h @@ -126,3 +126,4 @@ struct acm { #define SINGLE_RX_URB 2 #define NO_CAP_LINE 4 #define NOT_A_MODEM 8 +#define NO_DATA_INTERFACE 16 -- 2.20.1