https://projects.osmocom.org/https://projects.osmocom.org/favicon.ico?16647414092018-06-04T14:17:37ZOpen Source Mobile CommunicationsSIMtrace 2 - Bug #3318: out of boundaries get description during USB initialisationhttps://projects.osmocom.org/issues/3318?journal_id=97422018-06-04T14:17:37Ztsaitgaist
<ul></ul><p>note: SIMtrace will reboot until the host stops asking for description 238, which it does after a couple of tries.</p> SIMtrace 2 - Bug #3318: out of boundaries get description during USB initialisationhttps://projects.osmocom.org/issues/3318?journal_id=97692018-06-06T15:10:42Ztsaitgaist
<ul><li><strong>Status</strong> changed from <i>New</i> to <i>Resolved</i></li></ul><p>requesting string description 0xee is not a bug, it's a feature used by Microsoft Windows to further identify the USB device.<br />An overview of the technique is explained here: <a class="external" href="https://blogs.msdn.microsoft.com/usbcoreblog/2009/10/30/how-does-usb-stack-enumerate-a-device/">https://blogs.msdn.microsoft.com/usbcoreblog/2009/10/30/how-does-usb-stack-enumerate-a-device/</a><br />The full technique is described here: <a class="external" href="https://msdn.microsoft.com/en-us/windows/hardware/gg463179.aspx">https://msdn.microsoft.com/en-us/windows/hardware/gg463179.aspx</a><br />I am not sure why Linux does it, and I did not have any other USB device for which this happens.</p>
<p>The solution is to respond to this request with an empty packet, instead of stalling.<br />Not sure if sending an empty string would be better.<br />The fix is in commit <a class="external" href="https://git.osmocom.org/simtrace2/commit/?h=kredon/simtrace&id=7f4f8983dd9cbb734fb30c6af70baab5daa75880">https://git.osmocom.org/simtrace2/commit/?h=kredon/simtrace&id=7f4f8983dd9cbb734fb30c6af70baab5daa75880</a></p>