libftdi Archives

Subject: Re: ftdi_read loses bytes (when latency is low)

From: Uwe Bonnes <bon@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx>
To: libftdi@xxxxxxxxxxxxxxxxxxxxxxx
Date: Mon, 1 Dec 2014 20:13:15 +0100
>>>>> "Hendrik" == Hendrik  <chasake@xxxxxxxxx> writes:

...
    Hendrik> * I checked with usbdump and it indeed seems that not all bytes
    Hendrik> are actually transferred over the USB bus * I know that the
    Hendrik> FTDI driver in windows seems to be polling all the time (if on
    Hendrik> 1 ms latency it sucks away 'kernel CPU' especially in our case
    Hendrik> with more than 1 FTDI connected and the port open) but the
    Hendrik> behaviour I see here does not happen (or VERY infrequently in
    Hendrik> Windows) * I am on kernel '3.16.3-031603-lowlatency', could the
    Hendrik> 'lowlatency' part be interfering?

Even another question:
Did you try asynchronous transfers (ftdi_read_data_submit)?
-- 
Uwe Bonnes                bon@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx

Institut fuer Kernphysik  Schlossgartenstrasse 9  64289 Darmstadt
--------- Tel. 06151 162516 -------- Fax. 06151 164321 ----------

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