Messages in this thread |  | | Date | Tue, 14 Jan 2003 11:54:52 +0000 (GMT) | From | Tigran Aivazian <> | Subject | Re: [PATCH] don't create regular files in devfs (fwd) |
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btw, I assumed that by "It" you meant the actual act of updating microcode on cpus. If you were referring to the ability to manipulate microcode file that I described, then "it" certainly does _not_ work if no devfs is present.
Unless the world has been turned upside down and device nodes now have a filesize stored somewhere? :)
Regards Tigran
On Tue, 14 Jan 2003, Tigran Aivazian wrote:
> On Tue, 14 Jan 2003, Christoph Hellwig wrote: > > > On Tue, Jan 14, 2003 at 09:34:52AM +0000, Tigran Aivazian wrote: > > > Hi Christoph, > > > > > > I don't know about mtrr (probably does it for the same reason) but the > > > reason why microcode driver uses a regular file is because it needs > > > something that only regular files can provide --- the file size. > > > > > > This is an easy external "signifier" as to whether a successfull microcode > > > update has occurred or not. > > > > It seems to work without that feature on systems that don't have devfs.. > > Of course it works without it. I never said it is a required feature, only > a very nice to have. Namely: > > a) if devfs is available it provides a regular file whose size can be > examined by applications and content read/written without much "fuss". In > particular it is very convenient to say "vi microcode" and examine the > content directly. If it was a device node then this would have been > impossible. > > b) if devfs is not available then a limited basic functionality is > provided --- i.e. just update the microcode on CPU(s) and write the log > messages in the kernel log. > > Btw, having a size of mtrr is also useful for a similar reason. > > Regards > Tigran > >
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