Re: [Linux-fbdev-devel] mode change policy

[James S. <jsi...@tr...>]

> > NOTE: If this is the case then most drivers are broken!!!!
> 
> Yes, that is why I asked whether someone knows driver which conforms
> to API...

Off the top of my head vfb.c. I have to go threw the other drivers to see
which one are correct and which are wrong :-(

> > They return a error instead. Also what is the policy for cards that can't
> > change modes. Right now most drivers return a -EINVAL if they can't change
> > a mode. Do we pass back the only mode the driver supports instead of
> > returning a error? 
> 
> If your vesafb runs in 1280x1024x32, setting 800x600x8 must
> succeed, but do nothing. 

So a userland app would assume the video mode is 800x600x8 since it worked
and was passed back it. Of course the results on the screen would be
totally wrong. Then how is a userland app to know what the real mode is?

> I still think that we should
> use highest possible value instead of returning error when we cannot
> round some value up to next possible value. For example vyres comes
> to my (and matroxfb) mind ;-)

I agree. This will especially be true when we support i2c to get monitor
info. Here will will be fudging the hslen etc for the best fit.