configurable device (and other) tables in the kernel ?

[Julian Elischer]

Luigi Rizzo wrote:
> On Thu, Feb 01, 2007 at 11:09:12AM -0500, John Baldwin wrote:
>> On Wednesday 31 January 2007 14:51, Luigi Rizzo wrote:
> ...
>>> We have several tables in our kernel and modules,
>>> containing at least device-id tables (pci, usb),
>>> quirks for certain devices, and maybe more (i am excluding
> ...
>> Windows and MAC OS X both use plain text files to hold things like PCI device 
>> IDs to match drivers to devices.  OS X uses an XML file format that lets you 
> 
> plain text files!
> 
> too obvious to think of it :)
> 
> but, where can i find an example of a piece of kernel code that can
> read from a file "safely" (i.e. say in the modevent handler or maybe
> at device probe time) ?
> Something like
> 
> 	char *load_file_into_kernel_memody(filename, max_size, &error);
> 
> I have looked at the kernel side of execve and kldload, they are not
> exactly straightforward (at least there are seveal indirections).
> Maybe there are other simpler ones ?
> 
>> list the PCI ID's a driver supports and the kernel auto-loads driver modules 
>> by matching on PCI IDs.  Many drivers can't be helped by this though, as they 
>> use the device ID for for device-specific behavior (such as em(4) or 
>> brgpy(4)).

I like the idea of specifying aliases..


"if you see XXXX then pretend you saw YYYY and treat it the same."

> 
> well, that's a two-phase process, if you have the above table-based
> mechanism, the kernel (actually the bus driver i would say) can
> load the [device_id -> driver] table (or tables, assuming
> each driver has its own file) to select and load the
> correct driver, and then the driver itself could use the same
> mechanism to load a [device_id -> quirks] table for internal use ?
> 
> cheers
> luigi
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