On 6/16/05, Ian Romanick <[EMAIL PROTECTED]> wrote: > Why would layering the DRM on top of the fbdev driver break DirectFB? I > (think I) understand the issues with actually merging the drivers, but > the more I dig into, for example, MGA DRM, the more convenient it seems > to have DRM on top of fbdev.
The rules of VT swap are that after swap you can reset the card and blank it's memory. Then when you swap back the first system has to recover. This implies that the merged DRM/fbdev driver has to either be able to recover from having it's hardware reset/blanked or the rules of VT swap need to change. Given the definition of VT swap, VT swap looks a lot like suspend/resume to me and I would like to have common code. Now the problems are: 1) The kernel suspend call goes into the fbdev driver. DRM does see it. 2) VT swap is a user space notification 3) previously fbdev had only a single client, the console. All consoles use the same hardware state - mode, framebuffer setup, etc. With Xegl fbdev now has two clients, console and Xegl. But fbdev only has one place to store the hardware settings. This didn't cause a problem before on VT swap since X keeps its version in user space. Now fbdev needs a new API for managing multiple copies of these settings. 4) It is legal to wipe VRAM on swap, all of VRAM needs to be saved. Instead of doing all that I've been attempting to change the rules of VT swap, but that is making people mad at me. In my changed system you need to stop Xegl, unload its drivers, then load DirectFB's drivers, instead of being able to hot key to it. -- Jon Smirl [EMAIL PROTECTED] ------------------------------------------------------- SF.Net email is sponsored by: Discover Easy Linux Migration Strategies from IBM. Find simple to follow Roadmaps, straightforward articles, informative Webcasts and more! Get everything you need to get up to speed, fast. http://ads.osdn.com/?ad_idt77&alloc_id492&op=click -- _______________________________________________ Dri-devel mailing list Dri-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/dri-devel
