Re: [PATCH RESEND v2 2/2] usb: udc: Try to clarify an error message
Hi Marek,
> >>> --- a/drivers/usb/gadget/udc/udc-core.c
> >>> +++ b/drivers/usb/gadget/udc/udc-core.c
> >>> @@ -323,6 +323,7 @@ err1:
> >>>int usb_gadget_probe_driver(struct usb_gadget_driver *driver)
> >>>{
> >>> struct usb_udc *udc = NULL;
> >>> + unsigned intudc_count = 0;
> >>> int ret;
> >>>> if (!driver || !driver->bind || !driver->setup)
> >>> @@ -330,12 +331,22 @@ int usb_gadget_probe_driver(struct
> >>> usb_gadget_driver *driver)
> >>>> mutex_lock(_lock);
> >>> list_for_each_entry(udc, _list, list) {
> >>> + udc_count++;
> >>> +
> >>> /* For now we take the first one */
> >>> if (!udc->driver)
> >>> goto found;
> >>> }
> >>>> -printf("couldn't find an available UDC\n");
> >>> + if (!udc_count)
> >>> + printf("No UDC available in the system\n");
> >>> + else
> >>> + /* When this happens, users should 'unbind '
> >>> + * using the output of 'dm tree' and looking at the line right
> >>> + * after the USB peripheral/device controller.
> >>> + */
> >>> + printf("All UDCs in use (%d available), use the unbind
> >>> command\n",
> >>> +udc_count);
> >>
> >> Users should really use 'bind' command in the first place, to avoid this
> >> guesswork to which UDC (on systems with multiple UDCs) a gadget gets bound
> >> to, and instead bind the gadget to specific UDC they want to bind it to.
> >> This code should then be removed entirely.
> >
> > There are two cases when this can happen:
> > * a single UDC (common) but a function already bound, there is no
> >guessing here
> > * two (or more) UDC and there is some guessing
> >
> > Before your cleanup, drivers would get automatically unbound from the
> > UDC to let the one being needed to bind.
>
> How did that ever work ?
I believe both commands (fastboot vs. network commands like dhcp, tftp,
etc) would automatically bind to the first UDC and unbind once the
command done. But you recently changed that.
> > This is no longer the case,
> > so there is a change in the CLI and I want to help people facing
> > this new problem with a slightly more comprehensive message because
> > people don't fully understand what USB is all about. We cannot
> > ask all U-Boot USB users to be U-Boot experts and USB experts. This
> > is just a little help.
>
> In that case, you have to handle the details like CMD_BIND may not be
> enabled, and CMD_DM may not be enabled.
If I understand correctly you would like this to be described:
CMD_BIND imply CMD_DM
USB_GADGET imply CMD_BIND
Currently there is:
CMD_BIND default y if USB_ETHER
Maybe we should instead have:
CMD_BIND default y if USB_GADGET
And perhaps I would even go further and change the dependency
direction, so:
USB_GADGET imply CMD_BIND
CMD_BIND imply CMD_DM
Would this work for you?
> But then, maybe what we want to do is fix the automatic switching of
> gadgets to make it work again ?
This is a longer term goal I guess.
> > In an ideal world, we will have the possibility to create
> > composite gadgets and all this can go away once it is well
> > integrated, I guess?
>
> I believe you would still have to do a disconnect/connect cycle even with a
> composite driver, you cannot just add functions to existing composite at
> runtime.
I have in mind an environment variable which could define the "default"
composite gadget that we want at boot time, but then if people want to
change the gadgets exposed they would indeed need some kind of
disconnect/connect machinery, agreed.
Thanks, Miquèl
Re: [PATCH RESEND v2 2/2] usb: udc: Try to clarify an error message
On 10/5/23 17:51, Miquel Raynal wrote:
Hi Marek,
ma...@denx.de wrote on Thu, 5 Oct 2023 15:04:25 +0200:
On 10/2/23 15:46, Miquel Raynal wrote:
At some point when trying to use USB gadgets, two situations may arise
and lead to a failure. Either the UDC (USB Device Controller) is not
available at all (not described or not probed) or the UDC is already in
use. For instance, as the USB Ethernet gadget remains bound to the UDC,
the use of any other USB gadget (fastboot, dfu, etc) *after* will always
fail with the "couldn't find an available UDC" error.
Let's give a more helpful message by making a difference between the two
cases. Let's also hint people who would get this error and grep it into
the sources a better explanation of what's wrong with their workflow.
Signed-off-by: Miquel Raynal
---
While doing this I really wanted to add "much more" error comments but I
faced another reality: often the messages are there but use
pr_err/log_err which is actually silenced by default with LOGLEVEL=3, so
I consider this unnecessary, as decreasing the loglevel will make these
messages appear. I would have expected errors to be displayed, but I
understand it makes the binaries even bigger.
Resend: no change.
Changes in v2:
* s/UDC/UDCs/. I kept the sentence as it was as the suggested form did
not sound well at all when there is only one UDC.
---
drivers/usb/gadget/udc/udc-core.c | 13 -
1 file changed, 12 insertions(+), 1 deletion(-)
diff --git a/drivers/usb/gadget/udc/udc-core.c
b/drivers/usb/gadget/udc/udc-core.c
index 7f73926cb3e..8405b03462e 100644
--- a/drivers/usb/gadget/udc/udc-core.c
+++ b/drivers/usb/gadget/udc/udc-core.c
@@ -323,6 +323,7 @@ err1:
int usb_gadget_probe_driver(struct usb_gadget_driver *driver)
{
struct usb_udc *udc = NULL;
+ unsigned intudc_count = 0;
int ret;
> if (!driver || !driver->bind || !driver->setup)
@@ -330,12 +331,22 @@ int usb_gadget_probe_driver(struct usb_gadget_driver
*driver)
> mutex_lock(_lock);
list_for_each_entry(udc, _list, list) {
+ udc_count++;
+
/* For now we take the first one */
if (!udc->driver)
goto found;
}
> - printf("couldn't find an available UDC\n");
+ if (!udc_count)
+ printf("No UDC available in the system\n");
+ else
+ /* When this happens, users should 'unbind '
+* using the output of 'dm tree' and looking at the line right
+* after the USB peripheral/device controller.
+*/
+ printf("All UDCs in use (%d available), use the unbind
command\n",
+ udc_count);
Users should really use 'bind' command in the first place, to avoid this
guesswork to which UDC (on systems with multiple UDCs) a gadget gets bound to,
and instead bind the gadget to specific UDC they want to bind it to. This code
should then be removed entirely.
There are two cases when this can happen:
* a single UDC (common) but a function already bound, there is no
guessing here
* two (or more) UDC and there is some guessing
Before your cleanup, drivers would get automatically unbound from the
UDC to let the one being needed to bind.
How did that ever work ?
This is no longer the case,
so there is a change in the CLI and I want to help people facing
this new problem with a slightly more comprehensive message because
people don't fully understand what USB is all about. We cannot
ask all U-Boot USB users to be U-Boot experts and USB experts. This
is just a little help.
In that case, you have to handle the details like CMD_BIND may not be
enabled, and CMD_DM may not be enabled. But then, maybe what we want to
do is fix the automatic switching of gadgets to make it work again ?
In an ideal world, we will have the possibility to create
composite gadgets and all this can go away once it is well
integrated, I guess?
I believe you would still have to do a disconnect/connect cycle even
with a composite driver, you cannot just add functions to existing
composite at runtime.
Re: [PATCH RESEND v2 2/2] usb: udc: Try to clarify an error message
Hi Marek,
ma...@denx.de wrote on Thu, 5 Oct 2023 15:04:25 +0200:
> On 10/2/23 15:46, Miquel Raynal wrote:
> > At some point when trying to use USB gadgets, two situations may arise
> > and lead to a failure. Either the UDC (USB Device Controller) is not
> > available at all (not described or not probed) or the UDC is already in
> > use. For instance, as the USB Ethernet gadget remains bound to the UDC,
> > the use of any other USB gadget (fastboot, dfu, etc) *after* will always
> > fail with the "couldn't find an available UDC" error.
> >
> > Let's give a more helpful message by making a difference between the two
> > cases. Let's also hint people who would get this error and grep it into
> > the sources a better explanation of what's wrong with their workflow.
> >
> > Signed-off-by: Miquel Raynal
> > ---
> > While doing this I really wanted to add "much more" error comments but I
> > faced another reality: often the messages are there but use
> > pr_err/log_err which is actually silenced by default with LOGLEVEL=3, so
> > I consider this unnecessary, as decreasing the loglevel will make these
> > messages appear. I would have expected errors to be displayed, but I
> > understand it makes the binaries even bigger.
> >
> > Resend: no change.
> >
> > Changes in v2:
> > * s/UDC/UDCs/. I kept the sentence as it was as the suggested form did
> >not sound well at all when there is only one UDC.
> > ---
> > drivers/usb/gadget/udc/udc-core.c | 13 -
> > 1 file changed, 12 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/usb/gadget/udc/udc-core.c
> > b/drivers/usb/gadget/udc/udc-core.c
> > index 7f73926cb3e..8405b03462e 100644
> > --- a/drivers/usb/gadget/udc/udc-core.c
> > +++ b/drivers/usb/gadget/udc/udc-core.c
> > @@ -323,6 +323,7 @@ err1:
> > int usb_gadget_probe_driver(struct usb_gadget_driver *driver)
> > {
> > struct usb_udc *udc = NULL;
> > + unsigned intudc_count = 0;
> > int ret;
> > > if (!driver || !driver->bind || !driver->setup)
> > @@ -330,12 +331,22 @@ int usb_gadget_probe_driver(struct usb_gadget_driver
> > *driver)
> > > mutex_lock(_lock);
> > list_for_each_entry(udc, _list, list) {
> > + udc_count++;
> > +
> > /* For now we take the first one */
> > if (!udc->driver)
> > goto found;
> > }
> > > - printf("couldn't find an available UDC\n");
> > + if (!udc_count)
> > + printf("No UDC available in the system\n");
> > + else
> > + /* When this happens, users should 'unbind '
> > +* using the output of 'dm tree' and looking at the line right
> > +* after the USB peripheral/device controller.
> > +*/
> > + printf("All UDCs in use (%d available), use the unbind
> > command\n",
> > + udc_count);
>
> Users should really use 'bind' command in the first place, to avoid this
> guesswork to which UDC (on systems with multiple UDCs) a gadget gets bound
> to, and instead bind the gadget to specific UDC they want to bind it to. This
> code should then be removed entirely.
There are two cases when this can happen:
* a single UDC (common) but a function already bound, there is no
guessing here
* two (or more) UDC and there is some guessing
Before your cleanup, drivers would get automatically unbound from the
UDC to let the one being needed to bind. This is no longer the case,
so there is a change in the CLI and I want to help people facing
this new problem with a slightly more comprehensive message because
people don't fully understand what USB is all about. We cannot
ask all U-Boot USB users to be U-Boot experts and USB experts. This
is just a little help.
In an ideal world, we will have the possibility to create
composite gadgets and all this can go away once it is well
integrated, I guess?
Thanks,
Miquèl
Re: [PATCH RESEND v2 2/2] usb: udc: Try to clarify an error message
On 10/2/23 15:46, Miquel Raynal wrote:
At some point when trying to use USB gadgets, two situations may arise
and lead to a failure. Either the UDC (USB Device Controller) is not
available at all (not described or not probed) or the UDC is already in
use. For instance, as the USB Ethernet gadget remains bound to the UDC,
the use of any other USB gadget (fastboot, dfu, etc) *after* will always
fail with the "couldn't find an available UDC" error.
Let's give a more helpful message by making a difference between the two
cases. Let's also hint people who would get this error and grep it into
the sources a better explanation of what's wrong with their workflow.
Signed-off-by: Miquel Raynal
---
While doing this I really wanted to add "much more" error comments but I
faced another reality: often the messages are there but use
pr_err/log_err which is actually silenced by default with LOGLEVEL=3, so
I consider this unnecessary, as decreasing the loglevel will make these
messages appear. I would have expected errors to be displayed, but I
understand it makes the binaries even bigger.
Resend: no change.
Changes in v2:
* s/UDC/UDCs/. I kept the sentence as it was as the suggested form did
not sound well at all when there is only one UDC.
---
drivers/usb/gadget/udc/udc-core.c | 13 -
1 file changed, 12 insertions(+), 1 deletion(-)
diff --git a/drivers/usb/gadget/udc/udc-core.c
b/drivers/usb/gadget/udc/udc-core.c
index 7f73926cb3e..8405b03462e 100644
--- a/drivers/usb/gadget/udc/udc-core.c
+++ b/drivers/usb/gadget/udc/udc-core.c
@@ -323,6 +323,7 @@ err1:
int usb_gadget_probe_driver(struct usb_gadget_driver *driver)
{
struct usb_udc *udc = NULL;
+ unsigned intudc_count = 0;
int ret;
if (!driver || !driver->bind || !driver->setup)
@@ -330,12 +331,22 @@ int usb_gadget_probe_driver(struct usb_gadget_driver
*driver)
mutex_lock(_lock);
list_for_each_entry(udc, _list, list) {
+ udc_count++;
+
/* For now we take the first one */
if (!udc->driver)
goto found;
}
- printf("couldn't find an available UDC\n");
+ if (!udc_count)
+ printf("No UDC available in the system\n");
+ else
+ /* When this happens, users should 'unbind '
+* using the output of 'dm tree' and looking at the line right
+* after the USB peripheral/device controller.
+*/
+ printf("All UDCs in use (%d available), use the unbind
command\n",
+ udc_count);
Users should really use 'bind' command in the first place, to avoid this
guesswork to which UDC (on systems with multiple UDCs) a gadget gets
bound to, and instead bind the gadget to specific UDC they want to bind
it to. This code should then be removed entirely.
Re: [PATCH RESEND v2 2/2] usb: udc: Try to clarify an error message
On lun., oct. 02, 2023 at 15:46, Miquel Raynal
wrote:
> At some point when trying to use USB gadgets, two situations may arise
> and lead to a failure. Either the UDC (USB Device Controller) is not
> available at all (not described or not probed) or the UDC is already in
> use. For instance, as the USB Ethernet gadget remains bound to the UDC,
> the use of any other USB gadget (fastboot, dfu, etc) *after* will always
> fail with the "couldn't find an available UDC" error.
>
> Let's give a more helpful message by making a difference between the two
> cases. Let's also hint people who would get this error and grep it into
> the sources a better explanation of what's wrong with their workflow.
>
> Signed-off-by: Miquel Raynal
Reviewed-by: Mattijs Korpershoek
> ---
> While doing this I really wanted to add "much more" error comments but I
> faced another reality: often the messages are there but use
> pr_err/log_err which is actually silenced by default with LOGLEVEL=3, so
> I consider this unnecessary, as decreasing the loglevel will make these
> messages appear. I would have expected errors to be displayed, but I
> understand it makes the binaries even bigger.
>
> Resend: no change.
>
> Changes in v2:
> * s/UDC/UDCs/. I kept the sentence as it was as the suggested form did
> not sound well at all when there is only one UDC.
> ---
> drivers/usb/gadget/udc/udc-core.c | 13 -
> 1 file changed, 12 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/usb/gadget/udc/udc-core.c
> b/drivers/usb/gadget/udc/udc-core.c
> index 7f73926cb3e..8405b03462e 100644
> --- a/drivers/usb/gadget/udc/udc-core.c
> +++ b/drivers/usb/gadget/udc/udc-core.c
> @@ -323,6 +323,7 @@ err1:
> int usb_gadget_probe_driver(struct usb_gadget_driver *driver)
> {
> struct usb_udc *udc = NULL;
> + unsigned intudc_count = 0;
> int ret;
>
> if (!driver || !driver->bind || !driver->setup)
> @@ -330,12 +331,22 @@ int usb_gadget_probe_driver(struct usb_gadget_driver
> *driver)
>
> mutex_lock(_lock);
> list_for_each_entry(udc, _list, list) {
> + udc_count++;
> +
> /* For now we take the first one */
> if (!udc->driver)
> goto found;
> }
>
> - printf("couldn't find an available UDC\n");
> + if (!udc_count)
> + printf("No UDC available in the system\n");
> + else
> + /* When this happens, users should 'unbind '
> + * using the output of 'dm tree' and looking at the line right
> + * after the USB peripheral/device controller.
> + */
> + printf("All UDCs in use (%d available), use the unbind
> command\n",
> +udc_count);
> mutex_unlock(_lock);
> return -ENODEV;
> found:
> --
> 2.34.1
Re: [PATCH RESEND v2 2/2] usb: udc: Try to clarify an error message
Hi Massimo, massimo.pegorer+...@gmail.com wrote on Mon, 2 Oct 2023 16:37:10 +0200: > Hi Miquel, > > Il giorno lun 2 ott 2023 alle ore 15:46 Miquel Raynal > ha scritto: > > > > At some point when trying to use USB gadgets, two situations may arise > > [...cut...] > > > Signed-off-by: Miquel Raynal > > --- > > While doing this I really wanted to add "much more" error comments but I > > faced another reality: often the messages are there but use > > pr_err/log_err which is actually silenced by default with LOGLEVEL=3, so > > I consider this unnecessary, as decreasing the loglevel will make these > > messages appear. I would have expected errors to be displayed, but I > > understand it makes the binaries even bigger. > > This is how it works for pr_err but not for log_err: if you are not > using CONFIG_LOG, all log_xxx with level less than or equal to INFO > are in the binary. On the other hand, if you have CONFIG_LOG=y, > log_xxx are left out based on LOG_MAX_LEVEL value, while pr_xxx are > left out based on both LOGLEVEL and LOG_MAX_LEVEL too (due to the fact > that pr_xxx relies on log_xxx). This is quite confusing IMO. I'm > working on a proposal for a simpler and clearer unified way to log in > U-Boot. Very interesting (and, as you said, way too confusing). I did not even notice the difference, thanks for the explanation. Indeed, it would be nice to simplify this a bit. Thanks, Miquèl
Re: [PATCH RESEND v2 2/2] usb: udc: Try to clarify an error message
Hi Miquel, Il giorno lun 2 ott 2023 alle ore 15:46 Miquel Raynal ha scritto: > > At some point when trying to use USB gadgets, two situations may arise [...cut...] > Signed-off-by: Miquel Raynal > --- > While doing this I really wanted to add "much more" error comments but I > faced another reality: often the messages are there but use > pr_err/log_err which is actually silenced by default with LOGLEVEL=3, so > I consider this unnecessary, as decreasing the loglevel will make these > messages appear. I would have expected errors to be displayed, but I > understand it makes the binaries even bigger. This is how it works for pr_err but not for log_err: if you are not using CONFIG_LOG, all log_xxx with level less than or equal to INFO are in the binary. On the other hand, if you have CONFIG_LOG=y, log_xxx are left out based on LOG_MAX_LEVEL value, while pr_xxx are left out based on both LOGLEVEL and LOG_MAX_LEVEL too (due to the fact that pr_xxx relies on log_xxx). This is quite confusing IMO. I'm working on a proposal for a simpler and clearer unified way to log in U-Boot. Regards, Massimo > Resend: no change. > [...cut...]
[PATCH RESEND v2 2/2] usb: udc: Try to clarify an error message
At some point when trying to use USB gadgets, two situations may arise
and lead to a failure. Either the UDC (USB Device Controller) is not
available at all (not described or not probed) or the UDC is already in
use. For instance, as the USB Ethernet gadget remains bound to the UDC,
the use of any other USB gadget (fastboot, dfu, etc) *after* will always
fail with the "couldn't find an available UDC" error.
Let's give a more helpful message by making a difference between the two
cases. Let's also hint people who would get this error and grep it into
the sources a better explanation of what's wrong with their workflow.
Signed-off-by: Miquel Raynal
---
While doing this I really wanted to add "much more" error comments but I
faced another reality: often the messages are there but use
pr_err/log_err which is actually silenced by default with LOGLEVEL=3, so
I consider this unnecessary, as decreasing the loglevel will make these
messages appear. I would have expected errors to be displayed, but I
understand it makes the binaries even bigger.
Resend: no change.
Changes in v2:
* s/UDC/UDCs/. I kept the sentence as it was as the suggested form did
not sound well at all when there is only one UDC.
---
drivers/usb/gadget/udc/udc-core.c | 13 -
1 file changed, 12 insertions(+), 1 deletion(-)
diff --git a/drivers/usb/gadget/udc/udc-core.c
b/drivers/usb/gadget/udc/udc-core.c
index 7f73926cb3e..8405b03462e 100644
--- a/drivers/usb/gadget/udc/udc-core.c
+++ b/drivers/usb/gadget/udc/udc-core.c
@@ -323,6 +323,7 @@ err1:
int usb_gadget_probe_driver(struct usb_gadget_driver *driver)
{
struct usb_udc *udc = NULL;
+ unsigned intudc_count = 0;
int ret;
if (!driver || !driver->bind || !driver->setup)
@@ -330,12 +331,22 @@ int usb_gadget_probe_driver(struct usb_gadget_driver
*driver)
mutex_lock(_lock);
list_for_each_entry(udc, _list, list) {
+ udc_count++;
+
/* For now we take the first one */
if (!udc->driver)
goto found;
}
- printf("couldn't find an available UDC\n");
+ if (!udc_count)
+ printf("No UDC available in the system\n");
+ else
+ /* When this happens, users should 'unbind '
+* using the output of 'dm tree' and looking at the line right
+* after the USB peripheral/device controller.
+*/
+ printf("All UDCs in use (%d available), use the unbind
command\n",
+ udc_count);
mutex_unlock(_lock);
return -ENODEV;
found:
--
2.34.1
