On Fri, Sep 20, 2013 at 05:37:50AM +0800, Sarah Sharp wrote: > On Fri, Sep 13, 2013 at 03:50:48PM +0530, Pratyush Anand wrote: > > On Fri, Sep 13, 2013 at 3:40 PM, Xenia Ragiadakou <burzalodowa@xxxxxxxxx>wrote: > > > Nope :). There is still Kumar 's patch that keeps the wrappers, so it can > > > be applied instead of mine. But you did not tell me which tool you use > > > currently to log the mmio operations? it is useful to know. > > > > > > > > Sorry, I did not use any standard tool, rather I made local changes in > > dwc3_readl and dwc3_writel to log all dwc3 specific read/write > > operations into a static array, which was dumped to a text file using > > an ARM debugger (trace32) for further analysis. > > Would it be helpful to add a trace event for xHCI register reads and > writes (but not a debug statement)? That way you wouldn't have to > change or recompile the kernel at all, but you could use the trace > events infrastructure to enable xHCI register read/write debugging. We > wouldn't flood log files with register reads and writes, but a trace > event makes sense. I have not used tracepoints. So to understand, looked into Documentation/trace/tracepoints.txt: "When a tracepoint is "on", the function you provide is called each time the tracepoint is executed." So, do you mean to insert tracepoint in xhci_readl/writel? For sure it would be helpful, but... Trace ON will be needed only in very special (and a few) case, so would it be fine to insert a tiny time penalty in readl/writel routine when trace is off? Not Sure... Document says "When a tracepoint is "off" it has no effect, except for adding a tiny time penalty (checking a condition for a branch)" For me, you can take these patches. I can go with the way Paul suggested in special cases. Regards Pratyush > > AFAIK, trace events work on both x86 and ARM. > > Sarah Sharp -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
