Re: PATCH 2.2.18.9: Backport /proc/pci from 2.4.x to 2.2.x

From: Andrzej Krzysztofowicz (ankry@green.mif.pg.gda.pl)
Date: Mon Sep 25 2000 - 09:30:53 EST


>
> On Mon, 25 Sep 2000, Andrzej Krzysztofowicz wrote:
> > I mean moving the __init database compiled into kernel (based on pci.ids) to
> > a separate module, which would be responsible for on-demand updating of text
> > information (i.e. replacing VID:DID numbers with text).
>
> In early 2.3.x, the fbdev subsystem added "modedb", a feature which
> provides a standard video mode database for all framebuffer drivers.
> This is also __init code, because after boot, video mode information can
> be provided from userspace (via 'fbset', in fbdev's case).

I mean removing (optionally) the PCI device info *from* __init code to
minimize the on-disk kernel image (floppy boot) and *leave* the /proc/pci
funcionality of the system.

> I see you suggestion in the same way... If we keep the PCI device name
> data around after boot, then we have a lot of kernel memory locked up
> on the off chance that a HotPlug PCI device might appear for which we
> need a name.

I do not see any problem with any memory being locked. The master device
information persists in module code, which is unloaded just after use.
(IMHO, similar to __init code). Only necessary info (for really existing
devices) would be copied into kmalloc()ed kernel space. In a hotplug
device case it can be kfree()d while unplugging the device.

> I would much prefer a userspace solution for naming unnamed PCI devices
> after boot...

Maybe this would be even better as it does not do kernel locking (like
a module initializing routine). I am just not sure whether the kernel can
call such an userspace program automatically (eg. while initializing a
compiled-in hotplug device).

However, probably there's no much difference between kernel calling

modprobe -k some_module_setting_pci_info
rmmod some_module_setting_pci_info

and the same kernel calling some program, which does the same eg. via
sysctl().

Am I wrong ?

-- 
=======================================================================
  Andrzej M. Krzysztofowicz               ankry@mif.pg.gda.pl
  phone (48)(58) 347 14 61
Faculty of Applied Phys. & Math.,   Technical University of Gdansk
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