The theoretical maximum size is a little over 64k, since the length field is 16 bits. I think it would make sense to use that as a maximum in the kernel. <div class="gmail_quote">On Aug 19, 2012 3:40 PM, "Bjørn Mork" <<a href="mailto:bjorn@mork.no">bjorn@mork.no</a>> wrote: <blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"> Did anyone ever see a definite QMI message size specification? The qmi_wwan driver currently uses 512 bytes, but I do not remember where I got that from... Anyway, I am suspecting that it should be increased. I've been experimenting with injecting XTRA data to speed up GPS aquisition. Uploading chunks exceeding the driver message size (i.e. splitting the chunks in several USB control messages) does not seem to work. If I increase the driver message limit to 2048 bytes, I can successfully upload the XTRA database in 1536 byte chunks (which seems to be maximum supported). So I guess I should make this change to the driver, unless I was doing something wrong here. Has anyone else experimented with sending QMI messages > 512 bytes? But it would nice to quote a reference when making this change. Changing one arbitrary number for another arbitrary number looks bad. Bjørn _______________________________________________ libqmi-devel mailing list <a href="mailto:libqmi-devel@lists.freedesktop.org">libqmi-devel@lists.freedesktop.org</a> <a href="http://lists.freedesktop.org/mailman/listinfo/libqmi-devel" target="_blank">http://lists.freedesktop.org/mailman/listinfo/libqmi-devel</a> </blockquote></div>