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Message-ID: <9e4733910605020938h6a9829c0vc70dac326c0cdf46@mail.gmail.com>
Date: Tue, 2 May 2006 12:38:11 -0400
From: "Jon Smirl" <jonsmirl@gmail.com>
To: "Arjan van de Ven" <arjan@linux.intel.com>
Subject: Re: Add a "enable" sysfs attribute to the pci devices to allow userspace (Xorg) to enable devices without doing foul direct access
Cc: greg@kroah.com, linux-pci@atrey.karlin.mff.cuni.cz,
       linux-kernel@vger.kernel.org, airlied@linux.ie, pjones@redhat.com,
       akpm@osdl.org
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On 4/29/06, Arjan van de Ven <arjan@linux.intel.com> wrote:
> This patch adds an "enable" sysfs attribute to each PCI device. When read it
> shows the "enabled-ness" of the device, but you can write a "0" into it to
> disable a device, and a "1" to enable it.

What is the rationale for this? Doing this encourages people to write
device drivers in user space that probably should be a kernel driver.
What are you going to do if two competing apps want to set it to two
different states?

An alternate way to fix this problem is to write a device driver that
attaches to hardware with PCI class VGA. The driver could then provide
a device for each card found. By opening the device you can control
who owns and enables it.

We already have a lot of problems with multiple drivers trying to
control a single piece of hardware. Adding an "enable" attribute makes
it even easier to build conflicting drivers.

--
Jon Smirl
jonsmirl@gmail.com
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