> Face it, a good graphics driver needs more than just "set up the ROM". It > needs DMA access, and the ability to use interrupts. It needs a real > driver. > > It basically needs something like what the DRI modules tend to do. > > I'd be really happy to have real graphics drivers in the kernel, but quite > frankly, so far the abstractions I've seen have sucked dead donkeys > through a straw. "fbcon" does way too much (it's not a driver, it's more a > text delivery system and a mode switcher). And DRI is too complex and > fluid to be a good low-level driver.
Well... While I tend to agree, note that in 2.6 fbcon and the fbdev itself _do_ have been separated. The fbdevs are moving toward that low level driver thing. > Quite frankly, I'd much rather see a low-level graphics driver that does > _two_ things, and those things only: > > - basic hardware enumeration and setup (and no, "basic setup" does not > mean "mode switching": it literally means things like doing the > pci_enable_device() stuff. > > - serialization and arbitrary command queuing from a _trusted_ party (ie > it could take command lists from the X server, but not from untrusted > clients). This part basically boils down to "DMA and interrupts". This > is the part that allows others to wait for command completion, "enough > space in the ring buffers" etc. But it does _not_ know or care what the > commands are. IMHO, that low level driver should be ... the fbdev. The main reason for that is the necessary locking & synchronisation between the command flow and mode switching, palette control and cursor control (which aren't things doable via the normal command path on moth cases). > Then, fbcon and DRI and X could all three use these basics - and they'd be > _so_ basic that the hardware layer could be really stable (unlike the DRI > code that tends to have to upgrade for each new type of command that DRI > adds - since it has to take care of untrusted clients. So DRI would > basically use the low-level driver as a separate module, the way it > already uses AGP). I agree that fbcon itself should (and is now in 2.6) be a separate module. The interface is still scary, the locking is almost absent, which is a real problem even with current mode switching beeing racy with printk & blanking, but at least we have something that works and can evolve in the right direction. Look how the fbdev interface was simplified in the 2.4 -> 2.6 transition, it's really a lot saner now, and I hope it will continue to improve. > But I'm _not_ interested in some interfaces to let user mode just bypass > the kernel. Because they will not solve any of the other problems that > clearly _do_ need solving, and if the X server continues to believe that > it can just access the hardware directly, it will never play well together > with projects like fbcon/dri. Fully agreed. My point is that this low-level driver and the fbdev should be one thing. Ben. ------------------------------------------------------- This SF.net email is sponsored by: The SF.net Donation Program. Do you like what SourceForge.net is doing for the Open Source Community? Make a contribution, and help us add new features and functionality. Click here: http://sourceforge.net/donate/ _______________________________________________ Dri-devel mailing list [EMAIL PROTECTED] https://lists.sourceforge.net/lists/listinfo/dri-devel
