On Fri, Nov 21, 2008 at 12:28 PM, Devin Heitmueller <devin.heitmueller@xxxxxxxxx> wrote: > Hello, > > I am doing some driver work, and the USB device I am working on has > hardware pid filter support. > > Obviously if I don't implement such support, the kernel will do the > pid filtering. > > Does anyone have any experience with hardware pid filters, and have > they provided any signficant/visible benefit over the kernel pid > filter (either from a performance perspective or power consumption)? > This is aside from the known benefit that some streams would fit into > a full speed USB whereas before you might have required high speed > without the hardware pid filter. > > It's probably a good thing to implement in general for completeness, > but if there isn't any power or performance savings then I'm not sure > it's worth my time. > > Opinions welcome, > > Devin With the powerful systems around in this day & age, the gain of using hardware PID filters is hardly noticeable. Then again, you like to tweak things to the ultimate flexibility, and this is a good case for tweaking. While a system with a single usb2 stick will not be taxed at all by software PID filtering, there might be a slight performance enhancement in a system with 7 or 8 usb2 sticks using hardware PID filters rather than software. On the other hand, a device with hardware PID filters can be used on a USB1.1 port, which would normally not provide enough bandwidth for full transport using software filtering. So yes, there is a gain in using hardware PID filters, but 90% of the users would never notice the difference. -Mike _______________________________________________ linux-dvb mailing list linux-dvb@xxxxxxxxxxx http://www.linuxtv.org/cgi-bin/mailman/listinfo/linux-dvb
