[PATCH] USB: fix acm trouble with terminals
This patch fixes lost LF when ACM device is used with getty/login/bash,
in case of a modem which takes calls.
Signed-off-by: Pete Zaitcev <zaitcev@redhat.com>
Signed-off-by: Oliver Neukum <oliver@neukum.name>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/drivers/usb/class/cdc-acm.h b/drivers/usb/class/cdc-acm.h
index 9009114..963a5df 100644
--- a/drivers/usb/class/cdc-acm.h
+++ b/drivers/usb/class/cdc-acm.h
@@ -51,14 +51,34 @@
* Internal driver structures.
*/
+/*
+ * The only reason to have several buffers is to accomodate assumptions
+ * in line disciplines. They ask for empty space amount, receive our URB size,
+ * and proceed to issue several 1-character writes, assuming they will fit.
+ * The very first write takes a complete URB. Fortunately, this only happens
+ * when processing onlcr, so we only need 2 buffers.
+ */
+#define ACM_NWB 2
+struct acm_wb {
+ unsigned char *buf;
+ dma_addr_t dmah;
+ int len;
+ int use;
+};
+
struct acm {
struct usb_device *dev; /* the corresponding usb device */
struct usb_interface *control; /* control interface */
struct usb_interface *data; /* data interface */
struct tty_struct *tty; /* the corresponding tty */
struct urb *ctrlurb, *readurb, *writeurb; /* urbs */
- u8 *ctrl_buffer, *read_buffer, *write_buffer; /* buffers of urbs */
- dma_addr_t ctrl_dma, read_dma, write_dma; /* dma handles of buffers */
+ u8 *ctrl_buffer, *read_buffer; /* buffers of urbs */
+ dma_addr_t ctrl_dma, read_dma; /* dma handles of buffers */
+ struct acm_wb wb[ACM_NWB];
+ int write_current; /* current write buffer */
+ int write_used; /* number of non-empty write buffers */
+ int write_ready; /* write urb is not running */
+ spinlock_t write_lock;
struct usb_cdc_line_coding line; /* bits, stop, parity */
struct work_struct work; /* work queue entry for line discipline waking up */
struct tasklet_struct bh; /* rx processing */
@@ -71,7 +91,6 @@
unsigned int minor; /* acm minor number */
unsigned char throttle; /* throttled by tty layer */
unsigned char clocal; /* termios CLOCAL */
- unsigned char ready_for_write; /* write urb can be used */
unsigned char resubmit_to_unthrottle; /* throtteling has disabled the read urb */
unsigned int ctrl_caps; /* control capabilities from the class specific header */
};