Re: ftdi_sio: timing issue while setting ASYNC_LOW_LATENCY from user space

2017-08-28 Thread Matwey V. Kornilov
Hi all, I've just realized what is the reason for such long delays (~250ms) between setting ASYNC_LOW_LATENCY and starting receiving incoming data. Setting ASYNC_LOW_LATENCY leads to setting FTDI latency timer limit which is expressed in ms and allowed to be between 1ms and 255ms. Current default

Re: ftdi_sio: timing issue while setting ASYNC_LOW_LATENCY from user space

2017-08-28 Thread Matwey V. Kornilov
2017-08-28 11:22 GMT+03:00 Matwey V. Kornilov : > Hi all, > > I have an issue with the following patch: > c6dce2626606 ("USB: serial: ftdi_sio: fix extreme low-latency setting") > > I really need sub 16-ms latency for my peripheral and while I have no > problems with idea of setting ASYNC_LOW_LATEN

Re: ftdi_sio: timing issue while setting ASYNC_LOW_LATENCY from user space

2017-08-28 Thread Matwey V. Kornilov
2017-08-28 11:49 GMT+03:00 Greg KH : > On Mon, Aug 28, 2017 at 11:22:48AM +0300, Matwey V. Kornilov wrote: >> Hi all, >> >> I have an issue with the following patch: >> c6dce2626606 ("USB: serial: ftdi_sio: fix extreme low-latency setting") >> >> I really need sub 16-ms latency for my peripheral an

Re: ftdi_sio: timing issue while setting ASYNC_LOW_LATENCY from user space

2017-08-28 Thread Greg KH
On Mon, Aug 28, 2017 at 11:22:48AM +0300, Matwey V. Kornilov wrote: > Hi all, > > I have an issue with the following patch: > c6dce2626606 ("USB: serial: ftdi_sio: fix extreme low-latency setting") > > I really need sub 16-ms latency for my peripheral and while I have no > problems with idea of s

ftdi_sio: timing issue while setting ASYNC_LOW_LATENCY from user space

2017-08-28 Thread Matwey V. Kornilov
Hi all, I have an issue with the following patch: c6dce2626606 ("USB: serial: ftdi_sio: fix extreme low-latency setting") I really need sub 16-ms latency for my peripheral and while I have no problems with idea of setting ASYNC_LOW_LATENCY I would like point out that it doesn't work as expected a