[USB HID]Boot protocol Stack overflow

[MartKano]

Hello ! 

I'm struggling a bit with the USB HID boot protocol, I have a lot of stack overflow error when trying to do operations while in the get_report callback.

I know that I don't have to do time consuming operations while in callback, but not so big operation will make the stack to overflow.

Is there a way of increasing this stack ? 

note: 

I kept time consuming operations for the work queue but I still have to respond in the get report callback so minor operation should be accepted.

Thanks in advance.

Martin.

[ovrebekk]

Hi Martin

The time spent and the stack memory used is essentially two separate issues, and you need to be aware of them both, since they are not directly related. 

If you incur stack overflows often you might want to consider which variables you are putting on the stack and which you are not. Consider making larger arrays or structs static or global, to avoid them being put on the stack, since pushing a lot of data on the stack will also incur CPU overhead and increase runtime. 

As for increasing the stack size I assume it is the USB_WORKQUEUE_STACK_SIZE parameter you would need to change. You could try to set this to a larger value, and see if it solves the situation.

The default should be 1024 bytes, try larger values like 2048 or 4096 and see if it works better:

CONFIG_USB_WORKQUEUE_STACK_SIZE=4096

Best regards
Torbjørn

[MartKano]

Hi Torbjørn,

Sorry I was a bit tired when opening this topic and yes your right.

I'm already using the max stack size, the issues seems to come from my  architecture; since I'm using std::container..

I'll see if I need to change it later.

Thanks for the response. 

note : It would be nice to have a larger max usb workqueue size.

Best regards.

Martin.

[ovrebekk]

Hi Martin

Glad I could help. 

MartKano said:

note : It would be nice to have a larger max usb workqueue size.

Not sure what you mean. There shouldn't be any defined max size, as long as you have enough RAM available. 

Best regards
Torbjørn

[MartKano]

Hi Torbjorn,

My bad I thought the  USB_WORKQUEUE_STACK_SIZE was limited in the upper limit.

 

Kinds regards.

Martin.

[ovrebekk]

Hi Martin

Kconfig parameters generally don't define low and high limits, just one or more default values which might depend on other config parameters. 

I will close the ticket then

Best regards
Torbjørn