Date: Fri, 3 Jan 2014 21:59:57 +0900 From: "Lundberg, Johannes" <johannes@brilliantservice.co.jp> To: "freebsd-usb@freebsd.org" <freebsd-usb@freebsd.org>, Hans Petter Selasky <hps@bitfrost.no> Subject: usb_interrupt_read speed different on USB 2 vs 3 port. Message-ID: <CAASDrV=Onk2VbnSp-1s=XxJ0b89-M8--NWOeFPXjSgMLC8sVEA@mail.gmail.com>
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Hi I had a bug driving me crazy and I finally discovered something weird that was the reason. I have a pair of AR glasses from Vuzix which have a gyro/accelerometer/compass which I read from USB using usb_interrupt_read (reading 42 bytes of data). On my laptop I have two USB 2 and one USB 3 port. >From the USB 2 port things behave normally and reading takes a millisecond or so. >From the USB 3 port things get weird and the call to usb_interrupt_read takes over 20 milliseconds. I have been running this device on the same laptop for some time and haven't noticed this behavior before. Can it be something that has been introduced recently or perhaps only my system is behaving weird?... # uname -a FreeBSD PC 10.0-BETA1 FreeBSD 10.0-BETA1 #0: Sun Dec 8 16:15:23 JST 2013 root@PC:/usr/obj/usr/src/sys/GENERIC i386 Best regards -- Johannes Lundberg -- =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- $BHkL)J];}$K$D$$$F!'$3$NEE;R%a!<%k$O!"L>08?M$KAw?.$7$?$b$N$G$"$j!"HkF?FC8"$NBP>]$H$J$k>pJs$r4^$s$G$$$^$9!#(B $B$b$7!"L>08?M0J30$NJ}$,<u?.$5$l$?>l9g!"$3$N%a!<%k$NGK4~!"$*$h$S$3$N%a!<%k$K4X$9$k0l@Z$N3+<(!"(B $BJ#<L!"G[I[!"$=$NB>$NMxMQ!"$^$?$O5-:\FbMF$K4p$E$/$$$+$J$k9TF0$b$5$l$J$$$h$&$*4j$$?=$7>e$2$^$9!#(B --- CONFIDENTIALITY NOTE: The information in this email is confidential and intended solely for the addressee. Disclosure, copying, distribution or any other action of use of this email by person other than intended recipient, is prohibited. If you are not the intended recipient and have received this email in error, please destroy the original message.
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