From mboxrd@z Thu Jan 1 00:00:00 1970 From: "H. Peter Anvin" Subject: Re: [PATCH] drivers/char/mem.c: Add /dev/ioports, supporting 16-bit and 32-bit ports Date: Wed, 28 May 2014 14:41:52 -0700 Message-ID: <53865820.7010309@zytor.com> References: <20140509191914.GA7286@jtriplet-mobl1> <53729873.2030805@zytor.com> <20140515215646.GA16326@cloud> <63645237.lSKEVJUKkQ@wuerfel> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <63645237.lSKEVJUKkQ@wuerfel> Sender: linux-api-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Arnd Bergmann , josh-iaAMLnmF4UmaiuxdJuQwMA@public.gmane.org Cc: Greg Kroah-Hartman , akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-api-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-api@vger.kernel.org On 05/19/2014 05:36 AM, Arnd Bergmann wrote: > > My feeling is that all devices we can think of fall into at least one > of these categories: > > * legacy PC stuff that needs only byte access > * PCI devices that can be accessed through sysfs > * devices on x86 that can be accessed using iopl > I don't believe PCI I/O space devices can be accessed through sysfs, but perhaps I'm wrong? (mmapping I/O space is not portable.) -hpa