Re: [ANNOUNCE]: VM86 Daemon

[Antonino Daplas <adaplas@pol.net>]

On Tue, 2003-04-01 at 23:22, Jon Smirl wrote:
> > 
> > 5. fb_get_mode(int flags, int val, struct
> > fb_var_screeninfo *var, struct
> > fb_info *info)
> > 
> > - compute mode timings using GTF (refresh driven,
> > hsync driven, pixclock
> > driven, or maximized refresh) and place result in
> > var
> > 
> > #4 and #5 are already in fbmon.c
> >
> 
> Wouldn't it be better to make fb_get_mode only return
> the list of valid modes based on the hardware and
> monitor (if available) combination rather than letting
> the app sort it out?

Actually, using a combination of functions that will be available in
fbmon.c, the fbdev driver will become independent from userland, such as
/etc/fb.modes. User-entered timings are still preferred thoug, and only
when the timings are invalid that the driver will select the nearest
mode from the database, or calculate one for it.  A theoretical sequence
will be like this:

1. driver rounds off values in var
2. timings in var is validated using fb_validate_mode()
3. if timings are valid, driver accepts the new timings
4. if timings are invalid, it checks if monitor is GTF capable.
5. if monitor is GTF capable, it calls fb_get_mode(). 
6. if monitor is not GTF capable, it calls fb_find_mode(), passing the
database created from fb_create_modedb().

Fbdev needs this independence from userland in order for stty to work,
primarily, and to make it easier for the user, secondarily.

You're correct though that it's a good idea to pass a list of modelines
to userland.  However, the filtering is best done by the driver because
it has the best knowledge on the limits/capabilities of the chipset.

BTW:  fb_get_mode() will only compute a single modeline (using GTF). 
It's fb_create_modedb() that will make a list of video modes.

Tony



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