Re: radeon-pre-2

Vladimir Dergachev
2004-09-11T18:06:48Z

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@gmail.com
>