[PATCH RESEND v2 1/2] cmd: bind: Try to improve the (un)bind help
While it may sound totally obvious for the regular U-Boot developer to get the parameters of the bind/unbind commands from the output of 'dm tree', it did not felt straightforward to me until I was explicitly told to look there. And even when I knew the command, I did not make a direct link between the arguments of this command and the columns returned by 'dm tree'.
Several of us lost a lot of time because of that, I would like to kindly help other users by slightly improving this textual line. Unfortunately, because of how this string is used (like within the 'help' command) I cannot detail much more, but at least the pointer is there.
Signed-off-by: Miquel Raynal miquel.raynal@bootlin.com --- Resend: no change.
Changes in v2: * Moved the details in the long text section as suggested by Heinrich. * Rephrased the help text as well, not fully following Heinrich suggestion, but taking inspiration from it. --- cmd/bind.c | 4 ++++ 1 file changed, 4 insertions(+)
diff --git a/cmd/bind.c b/cmd/bind.c index 4d1b7885e60..be0d4d2a711 100644 --- a/cmd/bind.c +++ b/cmd/bind.c @@ -246,6 +246,8 @@ U_BOOT_CMD( "Bind a device to a driver", "<node path> <driver>\n" "bind <class> <index> <driver>\n" + "Use 'dm tree' to list all devices registered in the driver model,\n" + "their path, class, index and current driver.\n" );
U_BOOT_CMD( @@ -254,4 +256,6 @@ U_BOOT_CMD( "<node path>\n" "unbind <class> <index>\n" "unbind <class> <index> <driver>\n" + "Use 'dm tree' to list all devices registered in the driver model,\n" + "their path, class, index and current driver.\n" );
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 miquel.raynal@bootlin.com --- 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 int udc_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(&udc_lock); list_for_each_entry(udc, &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 <class> <index>' + * 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(&udc_lock); return -ENODEV; found:
Hi Miquel,
Il giorno lun 2 ott 2023 alle ore 15:46 Miquel Raynal miquel.raynal@bootlin.com ha scritto:
At some point when trying to use USB gadgets, two situations may arise
[...cut...]
Signed-off-by: Miquel Raynal miquel.raynal@bootlin.com
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...]
Hi Massimo,
massimo.pegorer+oss@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 miquel.raynal@bootlin.com ha scritto:
At some point when trying to use USB gadgets, two situations may arise
[...cut...]
Signed-off-by: Miquel Raynal miquel.raynal@bootlin.com
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
On lun., oct. 02, 2023 at 15:46, Miquel Raynal miquel.raynal@bootlin.com 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 miquel.raynal@bootlin.com
Reviewed-by: Mattijs Korpershoek mkorpershoek@baylibre.com
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 int udc_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(&udc_lock); list_for_each_entry(udc, &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 <class> <index>'* 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);found:
2.34.1
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 miquel.raynal@bootlin.com
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 int udc_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(&udc_lock); list_for_each_entry(udc, &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 <class> <index>'* 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.
Hi Marek,
marex@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 miquel.raynal@bootlin.com
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 int udc_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(&udc_lock);
list_for_each_entry(udc, &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 <class> <index>'* 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
On 10/5/23 17:51, Miquel Raynal wrote:
Hi Marek,
marex@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 miquel.raynal@bootlin.com
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 int udc_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(&udc_lock);
list_for_each_entry(udc, &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 <class> <index>'* 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.
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 int udc_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(&udc_lock);
list_for_each_entry(udc, &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 <class> <index>'* 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
On Mon, 2 Oct 2023 at 07:46, Miquel Raynal miquel.raynal@bootlin.com wrote:
While it may sound totally obvious for the regular U-Boot developer to get the parameters of the bind/unbind commands from the output of 'dm tree', it did not felt straightforward to me until I was explicitly told to look there. And even when I knew the command, I did not make a direct link between the arguments of this command and the columns returned by 'dm tree'.
Several of us lost a lot of time because of that, I would like to kindly help other users by slightly improving this textual line. Unfortunately, because of how this string is used (like within the 'help' command) I cannot detail much more, but at least the pointer is there.
Signed-off-by: Miquel Raynal miquel.raynal@bootlin.com
Resend: no change.
Changes in v2:
- Moved the details in the long text section as suggested by Heinrich.
- Rephrased the help text as well, not fully following Heinrich suggestion, but taking inspiration from it.
cmd/bind.c | 4 ++++ 1 file changed, 4 insertions(+)
Reviewed-by: Simon Glass sjg@chromium.org
On lun., oct. 02, 2023 at 15:46, Miquel Raynal miquel.raynal@bootlin.com wrote:
While it may sound totally obvious for the regular U-Boot developer to get the parameters of the bind/unbind commands from the output of 'dm tree', it did not felt straightforward to me until I was explicitly told to look there. And even when I knew the command, I did not make a direct link between the arguments of this command and the columns returned by 'dm tree'.
Several of us lost a lot of time because of that, I would like to kindly help other users by slightly improving this textual line. Unfortunately, because of how this string is used (like within the 'help' command) I cannot detail much more, but at least the pointer is there.
Signed-off-by: Miquel Raynal miquel.raynal@bootlin.com
Reviewed-by: Mattijs Korpershoek mkorpershoek@baylibre.com
Resend: no change.
Changes in v2:
- Moved the details in the long text section as suggested by Heinrich.
- Rephrased the help text as well, not fully following Heinrich suggestion, but taking inspiration from it.
cmd/bind.c | 4 ++++ 1 file changed, 4 insertions(+)
diff --git a/cmd/bind.c b/cmd/bind.c index 4d1b7885e60..be0d4d2a711 100644 --- a/cmd/bind.c +++ b/cmd/bind.c @@ -246,6 +246,8 @@ U_BOOT_CMD( "Bind a device to a driver", "<node path> <driver>\n" "bind <class> <index> <driver>\n"
- "Use 'dm tree' to list all devices registered in the driver model,\n"
- "their path, class, index and current driver.\n"
);
U_BOOT_CMD( @@ -254,4 +256,6 @@ U_BOOT_CMD( "<node path>\n" "unbind <class> <index>\n" "unbind <class> <index> <driver>\n"
- "Use 'dm tree' to list all devices registered in the driver model,\n"
- "their path, class, index and current driver.\n"
);
2.34.1
On 10/2/23 15:46, Miquel Raynal wrote:
While it may sound totally obvious for the regular U-Boot developer to get the parameters of the bind/unbind commands from the output of 'dm tree', it did not felt straightforward to me until I was explicitly told to look there. And even when I knew the command, I did not make a direct link between the arguments of this command and the columns returned by 'dm tree'.
Several of us lost a lot of time because of that, I would like to kindly help other users by slightly improving this textual line. Unfortunately, because of how this string is used (like within the 'help' command) I cannot detail much more, but at least the pointer is there.
Signed-off-by: Miquel Raynal miquel.raynal@bootlin.com
Resend: no change.
Changes in v2:
- Moved the details in the long text section as suggested by Heinrich.
- Rephrased the help text as well, not fully following Heinrich suggestion, but taking inspiration from it.
cmd/bind.c | 4 ++++ 1 file changed, 4 insertions(+)
diff --git a/cmd/bind.c b/cmd/bind.c index 4d1b7885e60..be0d4d2a711 100644 --- a/cmd/bind.c +++ b/cmd/bind.c @@ -246,6 +246,8 @@ U_BOOT_CMD( "Bind a device to a driver", "<node path> <driver>\n" "bind <class> <index> <driver>\n"
"Use 'dm tree' to list all devices registered in the driver model,\n"
"their path, class, index and current driver.\n" );
U_BOOT_CMD(
@@ -254,4 +256,6 @@ U_BOOT_CMD( "<node path>\n" "unbind <class> <index>\n" "unbind <class> <index> <driver>\n"
- "Use 'dm tree' to list all devices registered in the driver model,\n"
- "their path, class, index and current driver.\n"
'dm tree' depends on CMD_DM , you might need some if (IS_ENABLED()) here.
Hi Marek,
marex@denx.de wrote on Thu, 5 Oct 2023 15:01:51 +0200:
On 10/2/23 15:46, Miquel Raynal wrote:
While it may sound totally obvious for the regular U-Boot developer to get the parameters of the bind/unbind commands from the output of 'dm tree', it did not felt straightforward to me until I was explicitly told to look there. And even when I knew the command, I did not make a direct link between the arguments of this command and the columns returned by 'dm tree'.
Several of us lost a lot of time because of that, I would like to kindly help other users by slightly improving this textual line. Unfortunately, because of how this string is used (like within the 'help' command) I cannot detail much more, but at least the pointer is there.
Signed-off-by: Miquel Raynal miquel.raynal@bootlin.com
Resend: no change.
Changes in v2:
- Moved the details in the long text section as suggested by Heinrich.
- Rephrased the help text as well, not fully following Heinrich suggestion, but taking inspiration from it.
cmd/bind.c | 4 ++++ 1 file changed, 4 insertions(+)
diff --git a/cmd/bind.c b/cmd/bind.c index 4d1b7885e60..be0d4d2a711 100644 --- a/cmd/bind.c +++ b/cmd/bind.c @@ -246,6 +246,8 @@ U_BOOT_CMD( "Bind a device to a driver", "<node path> <driver>\n" "bind <class> <index> <driver>\n"
- "Use 'dm tree' to list all devices registered in the driver model,\n"
- "their path, class, index and current driver.\n" );
U_BOOT_CMD(@@ -254,4 +256,6 @@ U_BOOT_CMD( "<node path>\n" "unbind <class> <index>\n" "unbind <class> <index> <driver>\n"
- "Use 'dm tree' to list all devices registered in the driver model,\n"
- "their path, class, index and current driver.\n"
'dm tree' depends on CMD_DM , you might need some if (IS_ENABLED()) here.
Well, no, and that's my point actually. People need to know that this command exist and should be used for this purpose. If you only tell them "use 'dm tree'" conditionally, you loose part of the audience: people not aware of this command or its usefulness.
Thanks, Miquèl
On 10/5/23 17:54, Miquel Raynal wrote:
Hi Marek,
marex@denx.de wrote on Thu, 5 Oct 2023 15:01:51 +0200:
On 10/2/23 15:46, Miquel Raynal wrote:
While it may sound totally obvious for the regular U-Boot developer to get the parameters of the bind/unbind commands from the output of 'dm tree', it did not felt straightforward to me until I was explicitly told to look there. And even when I knew the command, I did not make a direct link between the arguments of this command and the columns returned by 'dm tree'.
Several of us lost a lot of time because of that, I would like to kindly help other users by slightly improving this textual line. Unfortunately, because of how this string is used (like within the 'help' command) I cannot detail much more, but at least the pointer is there.
Signed-off-by: Miquel Raynal miquel.raynal@bootlin.com
Resend: no change.
Changes in v2:
- Moved the details in the long text section as suggested by Heinrich.
- Rephrased the help text as well, not fully following Heinrich suggestion, but taking inspiration from it.
cmd/bind.c | 4 ++++ 1 file changed, 4 insertions(+)
diff --git a/cmd/bind.c b/cmd/bind.c index 4d1b7885e60..be0d4d2a711 100644 --- a/cmd/bind.c +++ b/cmd/bind.c @@ -246,6 +246,8 @@ U_BOOT_CMD( "Bind a device to a driver", "<node path> <driver>\n" "bind <class> <index> <driver>\n"
- "Use 'dm tree' to list all devices registered in the driver model,\n"
- "their path, class, index and current driver.\n" );
U_BOOT_CMD(@@ -254,4 +256,6 @@ U_BOOT_CMD( "<node path>\n" "unbind <class> <index>\n" "unbind <class> <index> <driver>\n"
- "Use 'dm tree' to list all devices registered in the driver model,\n"
- "their path, class, index and current driver.\n"
'dm tree' depends on CMD_DM , you might need some if (IS_ENABLED()) here.
Well, no, and that's my point actually. People need to know that this command exist and should be used for this purpose. If you only tell them "use 'dm tree'" conditionally, you loose part of the audience: people not aware of this command or its usefulness.
If you tell them 'Use "dm tree"' and it prints "no command found" , then it's a bug.
You likely want to add 'imply CMD_DM' into CMD_BIND Kconfig to make sure CMD_DM is available by default, but also that users can turn it off if they really want to.
participants (5)
-
Marek Vasut -
Massimo Pegorer -
Mattijs Korpershoek -
Miquel Raynal -
Simon Glass