Messages in this thread | | | Subject | Re: RFC: (re-)binding the VFIO platform driver to a platform device | From | Scott Wood <> | Date | Wed, 2 Oct 2013 13:32:38 -0500 |
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On Wed, 2013-10-02 at 13:25 -0500, Yoder Stuart-B08248 wrote: > > > -----Original Message----- > > From: Christoffer Dall [mailto:christoffer.dall@linaro.org] > > Sent: Wednesday, October 02, 2013 10:14 AM > > To: Alex Williamson > > Cc: Kim Phillips; gregkh@linuxfoundation.org; linux- > > kernel@vger.kernel.org; a.motakis@virtualopensystems.com; agraf@suse.de; > > Yoder Stuart-B08248; Wood Scott-B07421; Sethi Varun-B16395; Bhushan > > Bharat-R65777; peter.maydell@linaro.org; santosh.shukla@linaro.org; > > kvm@vger.kernel.org > > Subject: Re: RFC: (re-)binding the VFIO platform driver to a platform > > device > > > > Wouldn't a sysfs file to add compatibility strings to the vfio-platform > > driver make driver_match_device return true and make everyone happy? > > I had a similar thought. Why can't we do something like: > > echo "fsl,i2c" > /sys/bus/platform/drivers/vfio-platform/new_compatible > echo 12ce0000.i2c > /sys/bus/platform/drivers/vfio-platform/bind > > The first steps tell vfio-platform to register itself to handle > "fsl,i2c" compatible devices. The second step does the bind.
Needing to specify the compatible is hacky (we already know what device we want to bind; why do we need to scrounge up more information than that, and add a new sysfs interface for extending compatible matches, and a more flexible data structure to back that up?), and is racy on buses that can hotplug (which driver gets the new device?).
What's wrong with a non-vfio-specific flag that a driver can set, that indicates that the driver is willing to try to bind to any device on the bus if explicitly requested via the existing sysfs bind mechanism?
-Scott
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