* [PATCH] Fix default q_len for usb_f_printer gadget driver
@ 2020-10-30 22:34 Michael R Sweet
2020-10-30 23:24 ` Peter Chen
` (2 more replies)
0 siblings, 3 replies; 5+ messages in thread
From: Michael R Sweet @ 2020-10-30 22:34 UTC (permalink / raw)
To: Felipe Balbi; +Cc: Greg Kroah-Hartman, msweet, linux-usb, linux-kernel
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: Michael R Sweet <msweet@msweet.org>
---
drivers/usb/gadget/function/f_printer.c | 5 +++++
1 file changed, 5 insertions(+)
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
+#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 = 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)) {
--
2.17.1
^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: [PATCH] Fix default q_len for usb_f_printer gadget driver
2020-10-30 22:34 [PATCH] Fix default q_len for usb_f_printer gadget driver Michael R Sweet
@ 2020-10-30 23:24 ` Peter Chen
2020-11-30 14:17 ` Michael Sweet
[not found] ` <3EFD5A31-1794-4172-ADB6-CC2A74646D1D@msweet.org>
2 siblings, 0 replies; 5+ messages in thread
From: Peter Chen @ 2020-10-30 23:24 UTC (permalink / raw)
To: Michael R Sweet; +Cc: Felipe Balbi, Greg Kroah-Hartman, linux-usb, linux-kernel
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 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: Michael R Sweet <msweet@msweet.org>
Reviewed-by: Peter Chen <peter.chen@nxp.com>
Peter
> ---
> drivers/usb/gadget/function/f_printer.c | 5 +++++
> 1 file changed, 5 insertions(+)
>
> 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
>
> +#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 = 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)) {
> --
> 2.17.1
>
--
Thanks,
Peter Chen
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] Fix default q_len for usb_f_printer gadget driver
2020-10-30 22:34 [PATCH] Fix default q_len for usb_f_printer gadget driver Michael R Sweet
2020-10-30 23:24 ` Peter Chen
@ 2020-11-30 14:17 ` Michael Sweet
[not found] ` <3EFD5A31-1794-4172-ADB6-CC2A74646D1D@msweet.org>
2 siblings, 0 replies; 5+ messages in thread
From: Michael Sweet @ 2020-11-30 14:17 UTC (permalink / raw)
To: Felipe Balbi; +Cc: Greg Kroah-Hartman, linux-usb, linux-kernel
[-- Attachment #1: Type: text/plain, Size: 1973 bytes --]
Hi,
I submitted this a month ago, and aside from Peter Chen's "reviewed by" response I haven't heard anything nor seen it get merged. I know you are all really busy and I don't want to be a pest - is there something else I need to do to advance this patch?
Thanks!
> On Oct 30, 2020, at 6:34 PM, Michael R Sweet <msweet@msweet.org> wrote:
>
> 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: Michael R Sweet <msweet@msweet.org>
> ---
> drivers/usb/gadget/function/f_printer.c | 5 +++++
> 1 file changed, 5 insertions(+)
>
> 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
>
> +#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 = 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)) {
> --
> 2.17.1
>
________________________
Michael Sweet
[-- Attachment #2: Message signed with OpenPGP --]
[-- Type: application/pgp-signature, Size: 874 bytes --]
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: Fwd: [PATCH] Fix default q_len for usb_f_printer gadget driver
[not found] ` <3EFD5A31-1794-4172-ADB6-CC2A74646D1D@msweet.org>
@ 2020-12-10 4:47 ` Peter Chen
0 siblings, 0 replies; 5+ messages in thread
From: Peter Chen @ 2020-12-10 4:47 UTC (permalink / raw)
To: Michael Sweet, Greg Kroah-Hartman, Felipe Balbi; +Cc: linux-usb
On 20-12-10 02:38:13, Michael Sweet wrote:
> Peter,
>
> I know you had signed off on this patch at the end of October, but I haven't seen anything happen with it since then. As this is the first patch I've submitted, I don't know what else I need to do, if anything, to get it merged into the kernel sources?
>
Add Greg and Felipe.
Hi Michael,
Yes, I added my Reviewed-by tag at the end of Oct, but I am not the
maintainer for USB Gadget, so I can't add it to my tree.
Felipe is the maintainer of USB Gadget, the accepted patch will go to
his tree, and merge into the kernel.
Peter
> Thanks!
>
>
> > Begin forwarded message:
> >
> > From: Michael R Sweet <msweet@msweet.org>
> > Subject: [PATCH] Fix default q_len for usb_f_printer gadget driver
> > Date: October 30, 2020 at 6:34:19 PM EDT
> > To: Felipe Balbi <balbi@kernel.org>
> > Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>, msweet@msweet.org, linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org
> >
> > 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: Michael R Sweet <msweet@msweet.org>
> > ---
> > drivers/usb/gadget/function/f_printer.c | 5 +++++
> > 1 file changed, 5 insertions(+)
> >
> > 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
> >
> > +#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 = 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)) {
> > --
> > 2.17.1
> >
>
> ________________________
> Michael Sweet
>
>
>
--
Thanks,
Peter Chen
^ permalink raw reply [flat|nested] 5+ messages in thread
* [PATCH] Fix default q_len for usb_f_printer gadget driver
@ 2020-12-28 17:18 Michael R Sweet
0 siblings, 0 replies; 5+ messages in thread
From: Michael R Sweet @ 2020-12-28 17:18 UTC (permalink / raw)
To: Greg Kroah-Hartman; +Cc: Michael Sweet, linux-usb, linux-kernel, Felipe Balbi
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: Michael R Sweet <msweet@msweet.org>
---
drivers/usb/gadget/function/f_printer.c | 5 +++++
1 file changed, 5 insertions(+)
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
+#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 = 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)) {
--
2.17.1
^ permalink raw reply related [flat|nested] 5+ messages in thread
end of thread, other threads:[~2020-12-28 17:19 UTC | newest]
Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
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2020-10-30 22:34 [PATCH] Fix default q_len for usb_f_printer gadget driver Michael R Sweet
2020-10-30 23:24 ` Peter Chen
2020-11-30 14:17 ` Michael Sweet
[not found] ` <3EFD5A31-1794-4172-ADB6-CC2A74646D1D@msweet.org>
2020-12-10 4:47 ` Fwd: " Peter Chen
2020-12-28 17:18 Michael R Sweet
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