Pi vs Laptop

[aerolite]

I have done the following to be able to use my Logitech G27 on a PS4, mainly to use Project Cars.
I made two adapters following the DIY guide. One going the laptop route using windows, teensy 2 ect. Had a Pi2 available so wanted to try that as well as it would avoid the booting up of laptop, opening gimx launcher and hitting start.
The Pi2 is running Raspbian Jesse and Linux. Unit works well, just plug in power and it's ready to go in about 10 seconds.
Both adapters run the system well but I have noticed a difference in the force feedback. The FFB seems to be stronger when using the Pi, mainly in one parameter, when turning from one direction to the other, there is sometimes some good resistance and then a sudden "snap". The same feel is there using laptop but without the snap and not as much resistance. It's kind of hard to explain this feel, snap seems as close a description as I can come up with.
I have played around with many settings and after lots of adjusting of FFB withing pCars, the Pi has got better.
I have done research but can't find any mention here, has anyone else tried this.
Both units are running same software, same teensy 2, same adapter. I am thinking then that it must be the different processing of the two operating systems.
Any thoughts?
Thanks,
Steve

[Matlo]

Hi,
There are performance issues on the RPi that can sometimes make the FFB effects jerky.

[aerolite]

Thanks for the quick reply. I also have a RPi 1 Model B+ that I will try. Maybe that will act differently.

[Matlo]

I have a RPi 1 B+ and it also has the issue.
I think all the RPis have this issue due to hardware similarities.

[mstrVLT]

Try run gimx without "startx"

Or maybee overclock? ("raspi-config" in console)

Or add

usbhid.mousepoll=0

to /boot/cmdline.txt

Pls reply if problem is solved

... and Raspberry Pi 2, communicating with the SoC over a single USB channel ... is the bottleneck

The Pi uses a single usb 2.0 bus for Ethernet in addition to all usb ports.

A usb 2.0 bus can handle up to 480Mbits/s of bandwidth - a significant portion of that will be consumed by the overhead due to managing multiple devices, with exact numbers being hard to find, as they depend on each individual connected device, as well as what it is doing and how that is prioritized, but under worst-case scenarios can be up to 50%.

So now that we have essentially 5 devices that need to split the remaining 240Mbits/s of bandwidth, assuming that each one gets exactly 20%, we are left with 48 Mbits/s for a single device, or 6MB/s per device (since USB file transfers are usually measured via MB instead) - note that this number is the maximum combined for input and output, and that file transfers may have a significant amount of IO involved besides the actual transfer (especially with multiple, smaller files).

[Matlo]

Or add

usbhid.mousepoll=0

This is very likely to be counterproductive. I recommend to use a value of 2 on an average PC, and 4 on a RPi (or low-end PC).

[superbalza]

I have done the following to be able to use my Logitech G27 on a PS4, mainly to use Project Cars.
I made two adapters following the DIY guide. One going the laptop route using windows, teensy 2 ect. Had a Pi2 available so wanted to try that as well as it would avoid the booting up of laptop, opening gimx launcher and hitting start.
The Pi2 is running Raspbian Jesse and Linux. Unit works well, just plug in power and it's ready to go in about 10 seconds.
Both adapters run the system well but I have noticed a difference in the force feedback. The FFB seems to be stronger when using the Pi, mainly in one parameter, when turning from one direction to the other, there is sometimes some good resistance and then a sudden "snap". The same feel is there using laptop but without the snap and not as much resistance. It's kind of hard to explain this feel, snap seems as close a description as I can come up with.
I have played around with many settings and after lots of adjusting of FFB withing pCars, the Pi has got better.
I have done research but can't find any mention here, has anyone else tried this.
Both units are running same software, same teensy 2, same adapter. I am thinking then that it must be the different processing of the two operating systems.
Any thoughts?
Thanks,
Steve

I noticed the exactly same thing, comparing PC and Rpi2, and I noticed that when the FF "locks" (moments before the "snap"), the Rpi goes at 100% CPU usage... I'll try with the overclock... but what means "Try run gimx without "startx"?

[thurlesdrunk]

Any improvement to FFB with overclocking the pi?

[superbalza]

No, with overclock no changes at all... i still use a pc, by now for me it's working far more better...

[thurlesdrunk]

For me the same, FFB feels perfect using a laptop with ubuntu. With raspberry pi b+ I get the 'snap'. Will have to stick to laptop for now.