Re: [PATCH] kernel/resource.c: fix muxed resource handling in __request_region()

From: Vincent Pelletier
Date: Tue Feb 23 2016 - 02:58:00 EST


On Mon, 22 Feb 2016 13:49:12 +0000, Alan Cox <alan@xxxxxxxxxxxxxxx>
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