Date: Mon, 6 Mar 2017 11:41:42 +0100 From: Hans Petter Selasky <hps@selasky.org> To: Markus Rechberger <mrechberger@gmail.com> Cc: freebsd-multimedia@freebsd.org Subject: Re: What is wrong with FreeBSD and USB Support Message-ID: <9f51e1b1-d5df-afd3-f289-3bc55e417b5a@selasky.org> In-Reply-To: <CA%2BO4pCLqORoQFT3cpfzLvor1HyQcP0Pr1CQq7QJM_9r=rTspdg@mail.gmail.com> References: <CA%2BO4pCK4%2B1rE5ft4Boy_3xPdCxK31UtTQ2BYpnBUn5jxZr%2Bz_g@mail.gmail.com> <CA%2BO4pCJr5Bq-sgjzvZQB-mFRT6x7Tp3psga6f__V9Ag-=v-mhw@mail.gmail.com> <CA%2BO4pC%2Bf5xzOjENKSJu_sQeaiN3XL3WiTcRQvm4vVweQ71Xtrg@mail.gmail.com> <CA%2BO4pC%2B1t67ODF7bkyVhcojXTLnFkS28RbFAc%2Be-tjNncogMAQ@mail.gmail.com> <17db8b5b-9983-2ead-5c1d-960022afb1f6@selasky.org> <CA%2BO4pCLqORoQFT3cpfzLvor1HyQcP0Pr1CQq7QJM_9r=rTspdg@mail.gmail.com>
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On 03/06/17 11:37, Markus Rechberger wrote: > Are you sure? As from some of my signal analyzer dumps I do think that > all those systems support > multiple transfers within one completion event. I always request > multiple frames within one request on those systems and they complete > at once. And they only complete once all the buffers are filled. Yes, I'm 100% sure. If you look at their APIs you will have to submit individual jobs as a URB in Linux. If you want to send 128 x 333 bytes as 333 byte sized USB HighSpeed BULK packets, then Linux/MacOS and Windows force you to generate 128 URBs/Jobs to send the 128 packets. In FreeBSD a single USB transfers can send 128x 333 bytes. Only in the case where you send full-sized packets having an optional short-sized packet in the end, Linux/MacOS and Windows allows you to accumulate them into a single completion event. --HPS
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