> Hi Remi, Hi Laurent,
> You will find my latest version of the CPM2 FHCI patch attached to this e- > mail. I've never bothered to clean it as we decided to drop the USB host > function from our device. Thank you very much. Not clean is better than lost. > This depends on the disk. Some will probably not check the SOF token, others > will do and behave strangely. > >> Also 40% seems quite a lot, even at 1000Hz interruptions, an idea how much >> does the CRC computation contribute in this CPU hogging ? > > I haven't measured that, but probably not much. The biggest CPU time eater > isn't the SOF generation interrupt but the USB packet handling code. The CPM2 > USB host controller is really too low-level to be usable (except maybe for > specific applications). Comparing the OHCI/UHCI/EHCI and FHCI controllers is > akin to bit like comparing a full 16550 UART with a software bit-bang > implementation. You can get around with it, it might work for your specific > application, but you shouldn't try a full speed 115200bds communication while > computing a CPU-hungry physical simulation. That's what I was afraid of. I now understand clearly why you didn't expect that much better performance with CPM3 in a past message (http://ozlabs.org/pipermail/linuxppc-embedded/2008-May/030508.html). Still, as you said, it can have some use for specific applications. Do you remember the throughput you were able to reach with this cpu overhead ? > Laurent Pinchart > CSE Semaphore Belgium Kind regards, Rémi Lefèvre _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@ozlabs.org https://ozlabs.org/mailman/listinfo/linuxppc-dev
