On Tuesday 15 March 2005 16:55, Geert Uytterhoeven wrote:

On Tue, 15 Mar 2005, Antonino A. Daplas wrote:

quoted

On Tuesday 15 March 2005 11:43, Jon Smirl wrote:

quoted

Some discussion on the dri-egl list points out that the new mode
setting sysfs attributes for fbdev are too limited. Below is a
proposal I made on the dri-egl list.

To implement this for fbdev I need to know the right set of of
attribute value pairs. Some obvious ones are:

name=string
width=number
height=number
depth=number
refresh=number
interlace= yes | no | double
type = detailed|standard|vesa|user
sync = horizonatal_high | vertical_high | external | composite |
broadcast | green
left=number
right=number
lower=number
upper=number
hsync=number
vsync=number
pixclock=number

Right now fb0/modes is set by passing in an array of fb_videomode
structs. To convert this to attribute value pair I needs the full set
so that no info is lost.

If the mode and depth are independent variables we can end up with a
combo that exceeds monitor or hardware bandwidth. Would it be better
to combine the depth into the modes list? or if you try to set a

We can do that, vesa's mode id's are like that. Although I prefer that
mode setting should be separated from the framebuffer format setting (ie,
depth), it's currently difficult to make this work safely the reason
being that not all check_var() functions can be relied upon.

So should we separate into geometry, timings, visual (cfr. fbutils)?

Ideally, yes, but the problem with fbsysfs is that a regular user can change
the mode. Once we do the separation, combinations will exist that can be 
illegal.

ie echo 1024x768@60 > fb0/mode
   echo 32 > fb0/depth

The second set may not be compatible with the preceeding one.  Although
drivers do have a check_var(), I don't think all are robust enough to 
screen out illegal combinations.

Tony




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