Re: [Linux-fbdev-devel] [PATCH]: EDID parser

On  3 Apr 03 at 9:40, Sven Luther wrote:

On Thu, Apr 03, 2003 at 03:07:33AM +0100, Petr Vandrovec wrote:

quoted

On  2 Apr 03 at 22:55, James Simmons wrote:

quoted

It doesn't need a struct pci_dev in this case. It is possible to get this 
info from the i2c bus but I never seen any drivers do this. What data would
we have to pass in get the EDID inforamtion? So the question is how 
generic will get_EDID end up being or will we have to have driver specfic 
hooks since I don't pitcure i2c approaches being the same for each video 
card. Petr didn't you attempt this with the matrox driver at one time?

Yes, matroxfb provides one i2c (DDC) bus for each output videocard has.
I ended with only this support (and userspace EDID parser) as i2c was
initialized loong after framebuffer at that time... Now when i2c is usable
when fbdev initializes, it looks much better.

Only get_EDID interface I need is one which gets i2c bus as argument. But
I have no idea how I should handle situation where you have connected
two different monitors to both crtc1 outputs... Like 50Hz PAL TV &
60+Hz VGA monitor. Currently it is user responsibility to resolve such
situation...

Is the EDID reading stuff not done per head ?

No. With matroxfb, you have two framebuffer devices, /dev/fb0 & /dev/fb1,
which can be connected to any of three outputs: analog primary, analog
secondary and DVI. Analog primary & DVI share same pair of DDC cables,
and analog secondary has its own... And user can interconnect fb* with
outputs in almost any way he wants, as long as hardware supports it.
                                                        Petr Vandrovec