Re: radeon-pre-2

[Vladimir Dergachev]

On Sat, 11 Sep 2004, Jon Smirl wrote:
> > My view was that PLL setting (and setting of a fixed mode) would be done
> > in DRM driver. This way it would be able to restore previous settings
> > after a lockup or respond to FB request to change modes.
> >
> > However the decision of which mode to set, as well as where the
> > framebuffer is located is done in user-space. (So that subtleties of
> > layout of offscreen memory are not in the kernel).
> >
> > Jon - did I understand you correctly ?
>
> All register writes would occur in the driver. There is nothing
> stopping the code that computes those register values from running in
> user space.
>
> A example mode setting IO would take:
>  display buffer offset
>  width, height, stride, etc - for fbcon to use
>  register values to set the mode
>
> Mode setting needs to be serialized. It may be better to do the
> serialization before the hotplug event, in that case the mode setting
> IOCTL would be implicitly serialized and not need a separate lock.

Just to clear up things - do you plan to retain the knowledge of last mode 
set in the DRM driver ?

                           best

                             Vladimir Dergachev



> --
> Jon Smirl
> jonsmirl@xxxxxxxxx
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