On Mon, 22 Feb 2016 13:49:12 +0000, Alan Cox <a...@linux.intel.com> wrote: > It's not used much, especially nowdays. The use case is basically multi > I/O chips on the ISA/LPC bus with magic shared config register ports.
This is precisely a super I/O driver (gpio-f7188x) which, when used with concurrent accesses on an SMP machine triggered the issue which prompted this patch. In case information on the original issue is desired: My original report (ignore attached patch, it was rejected as it breaks other chips supported by this driver): http://permalink.gmane.org/gmane.linux.kernel.gpio/10204 My test procedure (second half of the mail), which I used to validate the patch against 4.1: http://permalink.gmane.org/gmane.linux.kernel.gpio/10216 Simon Guinot & Vincent Donnefort debugging results: http://permalink.gmane.org/gmane.linux.kernel.gpio/10521 Regards, -- Vincent Pelletier