Re: Re: [PATCH] HID: sony: Add force feedback support for Dualshock3 USB

[Sven Eckelmann <sven@narfation.org>]

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On Saturday 16 November 2013 17:30:25 simon@mungewell.org wrote:
> This patch appears to work OK with my DualShock/SixAxis controller (USB
> connection), but causes a machine lockup when used with my Intec wired
> controller.
> 
> The Intec controller works OK up to the point when I start rumble,
> sometimes the motor runs some times it doesn't. I am using SDL2's
> 'testhaptic' application.

Thanks a lot for this bug report. The testhaptic was a good testcase because 
it is a heavy user and can reproduce the problem quite easily. I've only 
tested it using testrumble and own programs which didn't seem to trigger the 
problem here. The problem is easy to explain:

 * usb_control_msg/usb_interrupt_msg/usb_bulk_msg/... may sleep
 * sony_play_effect may gets called in an softirq context (atomic)

So it is a bad choice to use hid_output_raw_report (which calls 
usb_control_msg) in a ff_memless control function. I will just send a revert 
patch in some minutes.

Kind regards,
	Sven

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