Jon Smirl <jonsmirl@...> wrote:
> I just scanned a couple of the fbdrivers and there seems to be no
> way to enumerate the modes that the hardware can support. This
> feature is probably lacking since there was no real use for it
> without the DDC monitor info.
Well without the DDC monitor info you cannot ensure that modes the
hardware can support will work on the attached monitor, but it is better
than now knowing what modes are available anyway. As it stands right now,
apps can simply call into the driver and 'try' to set any more that might
be supported, but good luck knowing if it will or if the monitor can
Also IMHO it is not a good idea to expect apps to pass down the CRTC and
pixel clock timings for the graphics card. It is nice to have this
programmable interface, but user land apps really just want to set a mode
and not have to deal with that stuff. Rarely they even care about the
refresh rate (just use a good one for the attached monitor).
> The fb modes are controlled via /etc/fb.modes
How do you mean they are controlled by /etc/fb.modes?
> On the other hand, the X windows drivers know how to enumerate the
> hardware supported modes. Just look at your XFree log and you can
> see a list of card supported modes vs monitor supported modes, and
> finally the pairs that match.
Yes, I am aware that XFree86 drivers can do this.
> The solution is to go lift the appropriate code out of the X
> windows drivers and add it to the fb ones.
Actually IMHO a better solution is the vesafbd project, since it would
allow framebuffer console drivers to be developed in user land, and could
then use the existing XFree86 driver modules without having to 'port'
them to the Linux kernel. Also with the vesafbd project it will be
possible to add support for reading the complete EDID from the monitor
using the VESA BIOS functions, so that the vesa framebuffer console
driver *could* know about the attached monitor and filter the available
modes that the VESA BIOS supports for the user applications.
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