Hello, I am studying the isp1760-hcd code, trying to figure out the logic of the data flow going in and out of the driver.
I have a few gaps in my understanding and was hoping to get help from you guys: 1. Once a PTD is schedule and its valid bit is set, what will trigger the isp1760 to scan its PTD list to find an active one that is pending to be done? EHCI spec mentioned "periodic scheduling", and if so is it controlled by DEFAULT_I_TDPS? Meaning, if I want it to be scanned more often, I should reduce this to say 512? (what is the cost of doing that? more interrupts?) 2. It seems that for OUT_PID, we setup the PTD and payload outside of interrupt context and then just update the number of bytes sent in the ISR. For IN_PID, we only setup the PTD outside interrupt context, but payload copying from the isp1760's payload space to the QTDs happen in interrupt context. I presume this is done so we don't miss any incoming data and that this approach is the standard practice? Thank you for everyone's time. -- Richard Retanubun -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
