On Wed, Jan 10, 2018 at 01:30:18PM +0800, Ji-Ze Hong (Peter Hong) wrote: > Hi Johan, > > Johan Hovold 於 2018/1/9 下午 07:08 寫道: > > On Thu, Jan 04, 2018 at 10:29:17AM +0800, Ji-Ze Hong (Peter Hong) wrote: > >> The F81532/534 had 4 clocksource 1.846/18.46/14.77/24MHz and baud rates > >> can be up to 1.5Mbits with 24MHz. > >> > >> This device may generate data overrun when baud rate setting to 921600bps > >> or higher with old UART trigger level setting (8x14=112) with full > >> loading. We'll change trigger level from 8x14=112 to 8x8=64 to avoid data > >> overrun. > >> > >> Also the read/write of EP0 will be affected by this patch. The worst case > >> of responding time is 20s when all serial port are full loading and trying > >> to access EP0, so we change EP0 timeout from 10 to 20s. > > > > Surely you meant 1 and 2 seconds respectively here? And if you have > > indeed measured response times close to 2000 ms then perhaps you want to > > add even more margin? > > Normally, the communication with F81534 ep0 will take less than 1 sec > (even only some milliseconds), but It maybe take much long time with > huge loading with UART functional. > > We had tested it on BurnInTest, 4 ports with 921600bps + MSR status > check to perform huge loading test. The worst case to read MSR register > via ep0 will take 15~18 seconds. So We'll still remain the max waiting > time for access ep0 with 2x10=20s in high baud rate mode. Wow, that's unfortunate. But note that your patch only doubles the timeout to 2000 ms, that is, two seconds and not twenty: -#define F81534_USB_TIMEOUT 1000 +#define F81534_USB_TIMEOUT 2000 If you really intended to increase this to twenty seconds, then please do so in a separate (preparatory) patch where you describe why that is needed (e.g. what you wrote above). Johan -- 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
