Messages in this thread | | | Date | Fri, 5 May 2006 14:10:56 -0700 | From | Greg KH <> | Subject | Re: Add a "enable" sysfs attribute to the pci devices to allow userspace (Xorg) to enable devices without doing foul direct access |
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On Fri, May 05, 2006 at 04:43:15PM -0400, Jon Smirl wrote: > >On 5/5/06, Greg KH <greg@kroah.com> wrote: > >> Who cares who "enabled" the device. Remember, the majority of PCI > >> devices in the system are not video ones. Lots of other types of > >> devices want this ability to enable PCI devices from userspace. I've > >> been talking with some people about how to properly write PCI drivers in > >> userspace, and this attribute is a needed part of it. > > The problem is not who 'enabled' the device. The problem is who owns > the state that has been loaded into the device. Without a mechanism > like open there is no way to serialize the programs trying to set > state into the device. > > fbdev and X have this fight currently. On every VT swap they each > reload their state into the video hardware. There is no coordination > so both systems have to assume worst case and rebuild everything. This > is not a good environment to program in. Every time one of the systems > starts using some new feature of hardware (like acceleration > functions) new state recovery code needs to be written.
Yes, I agree that this is a big issue and one that needs to be worked on. However, this simple "enable" file has nothing to do with that issue at all...
thanks,
greg k-h - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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