Commit ed054e4e authored by Michael R Sweet's avatar Michael R Sweet Committed by Greg Kroah-Hartman
Browse files

USB: gadget: f_printer: set a default q_len 



The usb_f_printer gadget driver uses a default q_len value of *0* which prevents
any IO from occurring.  Moreover, once the driver is instantiated it is
impossible to change the q_len value.

The following patch uses a default q_len value of 10 which matches the legacy
g_printer gadget driver.  This minimizes the possibility that you end up with a
non-working printer gadget.  It is still possible to set the q_len to a
different value using the configfs path of the same name.

Signed-off-by: default avatarMichael R Sweet <msweet@msweet.org>
Link: https://lore.kernel.org/r/9DFB1605-63A5-46DB-A5A4-B59B315D8115@msweet.org


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 7c9a2598

drivers/usb/gadget/function/f_printer.c

+5 −0
Original line number Diff line number Diff line
@@ -51,6 +51,8 @@ 
#define GET_PORT_STATUS		1

#define SOFT_RESET		2



#define DEFAULT_Q_LEN		10 /* same as legacy g_printer gadget */



static int major, minors;

static struct class *usb_gadget_class;

static DEFINE_IDA(printer_ida);
@@ -1363,6 +1365,9 @@ static struct usb_function_instance *gprinter_alloc_inst(void) 
	opts->func_inst.free_func_inst = gprinter_free_inst;

	ret = &opts->func_inst;



	/* Make sure q_len is initialized, otherwise the bound device can't support read/write! */

	opts->q_len = DEFAULT_Q_LEN;



	mutex_lock(&printer_ida_lock);



	if (ida_is_empty(&printer_ida)) {