Re: [libusb] Loosing connection to USB devices.

[David G. <dav...@gm...>]

The SOF packets are not directly controlled by software.

Since you have software that works and software that doesn't you are in a
good spot: you can get a USB protocol analyzer and look at the exact
packets being sent by the working software and make sure your own software
does the same thing.

--David

On Wed, Oct 12, 2022, 11:13 PM Jaco <ja...@jd...> wrote:

> Hi David.
>
>
>
> Does the host send the SOF packets or is it something I should do in the
> code?
>
> I am not sure if it is the code or what but I have to start looking
> somewhere to see why is it doing this.
>
> I also think that the inverter firmware is the issue but you know how it
> goes. They say nope it is not our side as our own software works fine.
>
> Some other third-party software also seems to work fine but it uses the
> Linux HIDRAW file based driver. So I am not sure if the HID driver does
> something else
>
> I use libusb and I see it will disconnect the kernel HIDRAW driver when my
> program starts.
>
>
>
> This is super frustrating as it all has been working for years and now on
> the new units we see this.
>
>
>
>
>
>
>
> *From:* David Grayson <dav...@gm...>
> *Sent:* Wednesday, October 12, 2022 6:29 PM
> *To:* Jaco <ja...@jd...>
> *Cc:* lib...@li...
> *Subject:* Re: [libusb] Loosing connection to USB devices.
>
>
>
> When the USB host is running, it normally broadcasts a Start of Frame
> (SOF) packet every millisecond (or maybe at a different rate depending on
> what USB speed you are using).  This should signal to all the devices that
> the bus is active and they need to stay awake and be ready to respond to
> packets they receive.  You might try using a USB protocol analyzer like the
> Beagle from Total Phase to see if those SOF packets are actually getting
> sent.  It's also possible that you are seeing a bug in the latest version
> of the inverter firmware.
>
>
>
> --David Grayson
>
>
>
>
>
> On Wed, Oct 12, 2022 at 5:56 AM Jaco <ja...@jd...> wrote:
>
> Hi all.
>
>
>
> I am not sure if this is a libusb issue. I do not think so. I just want to
> ask a question as I am not a USB guru.
>
> I have been using libusb for the last 3 years to communicate with solar
> inverters from the raspberry pi SBC.
>
> All is working 100%. The issue I have is that I started to see that the
> new inverters will shut down their USB port after a while.
>
>
>
> So my question is this. Is there some sort of hardware handshake / flow
> control like with serial to tell the USB device not to go into sleep mode?
>
> I have not needed it up till now but we are now seeing that a lot of new
> devices will go into “sleep” mode. Unplugging the USB device does not help.
>
> So I am not sure if this is a hardware issue to address with the inverter
> manufacturer or what is going on.
>
>
>
> Kind Regards.
>
>
>
>
>
>
>
> _______________________________________________
> libusb-devel mailing list
> lib...@li...
> https://lists.sourceforge.net/lists/listinfo/libusb-devel
>
>