<div dir="ltr">I started with a driver example I found online, then started extending and debugging. <br><br>I am finding that much of my problems are mainly timing issues. The example code for the USB is all blocking code, as such when using multiple composite devices, each device is blocking the other from getting processor and USB resources. <br><br>It is the kind of problem that is made for an RTOS or async/await language....<br><div><br></div><div>Trampas</div></div><br><div class="gmail_quote gmail_quote_container"><div dir="ltr" class="gmail_attr">On Thu, Feb 27, 2025 at 6:32 PM Glen Smith <<a href="mailto:mrglenasmith@gmail.com">mrglenasmith@gmail.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><p dir="ltr">Did you write the driver or is this another one of those times where you spend a fair bit of time pulling your hair out checking your own work only to discover it was someone else that caused the problem? </p>
<br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Thu, Feb 27, 2025, 2:45 PM Trampas Stern via TriEmbed <<a href="mailto:triembed@triembed.org" target="_blank">triembed@triembed.org</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr">I figured out that my driver was not sending a zero length packet after receiving the RNDIS Initialize message. This fixed the problem above, and now I am on to debugging the next issue.<div><br></div><div>Thanks</div><div>Trampas</div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Thu, Feb 27, 2025 at 9:50 AM Trampas Stern <<a href="mailto:trampas@gmail.com" rel="noreferrer" target="_blank">trampas@gmail.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr">I am trying to do USB RNDIS enumeration and having issues. I have googled and read everything I can find and keep running into issues. I get the enumeration working and it will work for days on my PC, then at some point it will not work. I switch hubs, ports and it might work again for days, then stop. <br><br>I have been using Saleae logic analyzer as well as USB protocol analyzer (Total Phase Beagle device) and have been unable to figure out the issues. <br><br>My initial thoughts were that Microsoft was doing some predictive analysis on device timing. That is, I noticed that if the USB request from the host came in too quickly it would cause issues. I figured that based on the packet NAKs that Microsoft might dynamically change request timing to compensate for slower devices. I figure this would maximize the bus bandwidth utilization by not sending packets that most likely would be NAK'd. I am not sure if this is true or not, but sounded reasonable? I since changed my device to be all interrupt driven for fastest response. This addressed some issues, but not all of my problems. <div><br></div><div>Now I seem to have hit another issue. The host sends an RNDIS Initialize message, after which I setup device's USB peripheral to send the RESPONSE_AVAILABLE message, however the host never seems to poll for the RESPONSE_AVAILABLE and then timeout on the RNDIS Initialize message. <br><br>I have previously seen this behavior and found that if I delayed setting up the RESPONSE_AVAILABLE message it would sometimes work. Specifically, I would send the REPONSE_AVAILABLE using main loop verses right away in the interrupt handler and it would work most of the time. This did not make any sense as that as I understand it the host has to poll for the RESPONSE_AVAILABLE so the timing of configuring peripheral to send message should not matter, since it is all host driven system. As I understand it the host does an interrupt polling messages to the RNDIS command end point to request the RESPONSE_AVAILABLE. I am not seeing and polling message from host (Windows) on the RNDIS interrupt end point. I do see EP0 polling, but not ones on the RNDIS command endpoint. </div><div><br>I was wondering if anyone had experience with USB and possibly could offer some advice, education, or help. I do have all kinds of data captures and logs etc.. </div><div><br></div><div>Thanks! </div><div>Trampas</div><div><br></div></div>
</blockquote></div>
_______________________________________________<br>
Triangle, NC Embedded Interest Group mailing list<br>
<br>
To post message: <a href="mailto:TriEmbed@triembed.org" rel="noreferrer" target="_blank">TriEmbed@triembed.org</a><br>
List info: <a href="http://mail.triembed.org/mailman/listinfo/triembed_triembed.org" rel="noreferrer noreferrer" target="_blank">http://mail.triembed.org/mailman/listinfo/triembed_triembed.org</a><br>
TriEmbed web site: <a href="https://TriEmbed.org" rel="noreferrer noreferrer" target="_blank">https://TriEmbed.org</a><br>
To unsubscribe, click link and send a blank message: mailto:<a href="mailto:unsubscribe-TriEmbed@bitser.net" rel="noreferrer" target="_blank">unsubscribe-TriEmbed@bitser.net</a>?subject=unsubscribe<br>
Searchable email archive available at <a href="https://www.mail-archive.com/triembed@triembed.org/" rel="noreferrer noreferrer" target="_blank">https://www.mail-archive.com/triembed@triembed.org/</a><br>
<br>
</blockquote></div>
</blockquote></div>