Hi Mark,
A few more comments:
> From: Mark McClelland [mailto:[EMAIL PROTECTED]]
>
> "Dunlap, Randy" wrote:
> >
> > Hi Mark,
> >
> > a. Do you NEED to leave the 2.2-backward compatibility code
> > in this driver? That's not the way Linus wants to see it
> > done. The backport should be able to take care of this,
> > although you may need to work with Vojtech on it.
>
> No, it's not necessary. It was from the CPiA driver found on
> Sourceforge
> so I thought it was kosher, but it looks like they removed it from the
> version that's in the kernel. I'll take it out and send you a patch.
Yep, saw that one.
> > b. I see that you are using /proc/ov511/video* and cpia uses
> > /proc/cpia/video*. I thought that drivers were supposed to
> > use /proc/driver/xxx for proc-fs data like this (or did I
> > dream that?). Or should v4l drivers use /proc/video/* or
> > /proc/v4l/* ? Is there any standard^W expectation on this?
>
> Again, I was just doing what the CPiA driver does, but that
> doesn't mean
> it's right, of course. I do agree that they should someplace else,
> though I don't know where. /proc/v4l seems good as it is
> consistent with /dev/v4l.
Alan (the v4l gnome) preferred /proc/video (as in /proc/video/ov511):
> There is no current standard here. I would prefer /proc/video/... as it
> keeps things less cluttered than /proc/randomcardifoundintheshed/...
Can you give me a patch with this also?
> > c. Is all of the floating point math done at compile
> > time? It can't stay in there if it's done at run time.
> > [I just noticed that it was in there previously.]
>
> It seems to compile down to integer math one way or another, and it
> seems to work fine, so I assume it is OK. I was pretty sure that basic
> floating point ops are OK in the kernel, but I am no expert on such
> things. Should I be saving and restoring the FPU registers or
> something?
There was just thread on linux-kernel last week about a driver
using floating point and how it can (theoretically) cause
random, unexpected occurrances.
No, you shouldn't be saving/restoring the FPU registers.
You just shouldn't be using FP in the kernel (at run-time).
The compile-time stuff that is in ov511 should be OK AFAIK.
> Incidentally, I was planning on using MMX/SSE/3DNOW
> eventually to speed
> things up, but is this even safe/doable in the kernel? Alan?
My understanding of MMX/SSE is that they have the same
requirements as the FPU. Their register set needs to be
saved/restored.
> --
> Mark McClelland
> [EMAIL PROTECTED]
~Randy
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