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x-ms-exchange-antispam-messagedata: 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 x-ms-exchange-transport-forked: True Content-Type: text/plain; charset="us-ascii" Content-ID: Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 X-OriginatorOrg: nxp.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-AuthSource: AM8PR04MB7300.eurprd04.prod.outlook.com X-MS-Exchange-CrossTenant-Network-Message-Id: 7fb4a2ca-0cb1-48ad-6554-08d87d2af301 X-MS-Exchange-CrossTenant-originalarrivaltime: 30 Oct 2020 23:24:29.1550 (UTC) X-MS-Exchange-CrossTenant-fromentityheader: Hosted X-MS-Exchange-CrossTenant-id: 686ea1d3-bc2b-4c6f-a92c-d99c5c301635 X-MS-Exchange-CrossTenant-mailboxtype: HOSTED X-MS-Exchange-CrossTenant-userprincipalname: 4//N+mOzyATmhTCE6xAZI9SWnWLv2jIrxXAsJf8krfZbL0Cc5DaL9C2QMxmOdm2uOFlZ0wS6WPXwE65k2cRxbQ== X-MS-Exchange-Transport-CrossTenantHeadersStamped: AM0PR0402MB3364 Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org On 20-10-30 18:34:19, Michael R Sweet wrote: > The usb_f_printer gadget driver uses a default q_len value of *0* which p= revents > any IO from occurring. Moreover, once the driver is instantiated it is > impossible to change the q_len value. >=20 > The following patch uses a default q_len value of 10 which matches the le= gacy > 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. >=20 > Signed-off-by: Michael R Sweet Reviewed-by: Peter Chen Peter > --- > drivers/usb/gadget/function/f_printer.c | 5 +++++ > 1 file changed, 5 insertions(+) >=20 > diff --git a/drivers/usb/gadget/function/f_printer.c b/drivers/usb/gadget= /function/f_printer.c > index 9c7ed2539ff7..4f3161005e4f 100644 > --- a/drivers/usb/gadget/function/f_printer.c > +++ b/drivers/usb/gadget/function/f_printer.c > @@ -50,6 +50,8 @@ > #define GET_PORT_STATUS 1 > #define SOFT_RESET 2 > =20 > +#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); > @@ -1317,6 +1319,9 @@ static struct usb_function_instance *gprinter_alloc= _inst(void) > opts->func_inst.free_func_inst =3D gprinter_free_inst; > ret =3D &opts->func_inst; > =20 > + /* Make sure q_len is initialized, otherwise the bound device can't sup= port read/write! */ > + opts->q_len =3D DEFAULT_Q_LEN; > + > mutex_lock(&printer_ida_lock); > =20 > if (ida_is_empty(&printer_ida)) { > --=20 > 2.17.1 >=20 --=20 Thanks, Peter Chen=