Re: [PATCH] PNP support for i8042 driver

From: matthieu castet
Date: Mon Nov 15 2004 - 14:54:11 EST

Dmitry Torokhov wrote:
On Sun, 14 Nov 2004 13:22:21 +0100, matthieu castet
<castet.matthieu@xxxxxxx> wrote:

Dmitry Torokhov wrote:

On Saturday 13 November 2004 08:23 am, matthieu castet wrote:

this patch add PNP support for the i8042 driver in 2.6.10-rc1-mm5. Acpi
is try before the pnp driver so if you don't disable ACPI or apply
others pnpacpi patches, it won't change anything.

Please review it and apply if possible


Matthieu CASTET

Signed-Off-By: Matthieu Castet <castet.matthieu@xxxxxxx>



Do we really need to keep those drivers loaded - i8042 will not
be hotplugged and ports are reserved anyway. We are only interested
in presence of the keyboard and mouse ports. Can we unregister
the drivers (both ACPI and PNP) right after registering and mark
all that stuff as __init/__initdata as in the patch below?

It is better to keep pnp driver loaded because when it unload, the
resources will be disabled, so for the motherboards that allow it the
irq won't work anymore, and so the keyboard and mouse won't work...

Is it possible to leave the device in enabled state or enable device
after unloading the driver with PNP?
Yes you could do a very ugly hack : set pnp_can_disable(dev) to 0 before unregister. With that the device won't be disabled (no resource desalocation), but the device will be mark as not active in pnp layer.

All we need from PNP layer
for i8042 is to verify presence of the KBC, we don't need resource
management.The ports range is already marked as reserved, IRQ
will be requested if needed...

I don't agree at all :
- the pci layer allow you to find the device like pnp layer, then you register resource with request_region or equivalent. Do we need to do the same for all pci driver ?
- actually the resources are registered in the kernel, but not in the bios, why some strange bios can allow to use irq 12 to an other device if it isn't used ?
- Do you save lot's of memory with __init/__initdata ? The pnp code is quite small.

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