On Thu, 27 May 2010, Alex Deucher wrote: > On Thu, May 27, 2010 at 2:56 AM, Guennadi Liakhovetski <g.liakhovetski@xxxxxx> wrote: ... > > Ok, let me explain what exactly I meant. Above I referred to "display > > drivers," which is not the same as a "framebuffer controller driver" or > > whatever you would call it. By framebuffer controller driver I mean a > > driver for the actual graphics engine on a certain graphics card or an > > SoC. This is the part, that reads data from the actual framebuffer and > > outputs it to some hardware interface to a display device. Now this > > interface can be a VGA or a DVI connector, it can be one of several bus > > types, used with various LCD displays. In many cases this is all you have > > to do to get the output to your display. But in some cases the actual > > display on the other side of this bus also requires a driver. That can be > > some kind of a smart display, it can be a panel with an attached display > > controller, that must be at least configured, say, over SPI, it can be a > > display, attached to the host over the MIPI DSI bus, and implementing some > > proprietary commands. In each of these cases you will have to write a > > display driver for this specific display or controller type, and your > > framebuffer driver will have to interface with that display driver. Now, > > obviously, those displays can be connected to a variety of host systems, > > in which case you will want to reuse that display driver. This means, > > there has to be a standard fb-driver - display-driver API. AFAICS, this is > > currently not implemented in fbdev, please, correct me if I am wrong. > > > Another API to consider in the drm kms (kernel modesetting) interface. > The kms API deals properly with advanced display hardware and > properly handles crtcs, encoders, and connectors. It also provides > fbdev api emulation. Well, is KMS planned as a replacement for both fbdev and user-space graphics drivers? I mean, if you'd be writing a new fb driver for a relatively simple embedded SoC, would KMS apriori be a preferred API? Thanks Guennadi --- Guennadi Liakhovetski, Ph.D. Freelance Open-Source Software Developer http://www.open-technology.de/ -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
