On Mon, Feb 16, 2004 at 01:30:33PM +0100, Helge Hafting wrote: > Ville Syrjälä wrote: > [...] > > > >I want to bypass the drm to do accel from user space. Doing an ioctl() for > >each blit feels very expensive. Rather than do an ioctl() for each blit > >the drm could check the commands in the DMA buffer for bad stuff. But that > >doesn't feel very efficient either. > If an ioctl per blit is expensive, why don't you make an ioctl > that accepts an arbitrarily long list of blits? > You keep a sequre interface, and keeps performance up by handing over > a lot of blits in one go.
And what if the app does a few blits and then draws a few lines and then some rectangle fills and then... If all of that is folded into one ioctl() it pretty much becomes identical to checking the raw DMA buffers for bad stuff. > >If you don't care about the security I > People care about security. A server shoudn't be able to fall over just > because someone plays quake on the console. And a home machine shouldn't > be less stable either, that isn't necessary. You can have both performance > and security. I didn't say everyone should not care. People can care if they need to. > >think you should be allowed to bypass it to gain some speed. > And you can gain quite a bit more by writing your high-performance > program for one particular card, one mode and one resolution. No > interfaces at all, only hardware accesses. That gave us nice performance > on the 1MHz machines of the > eighties. Nobody does it any more though. I'm not doint that. > >And finally I find the current situation with multi-head cards quite > >bad. I'd like the ablitity for a user space app to open the whole card > >as one entity. That includes all CRTCs, outputs and the whole memory > >(minus whatever is in use by other stuff like DMA stuff and video > >capture). If the app doesn't want to handle such details it would just get > >whatever is used by the current VT. > That might be useful, but it is also useful to be able to deal with only one > head at a time, so that another head may be used by another user. Yes I know. Actually if the video memory manager is moved to the kernel accessing all heads becomes as simple as opening all of them individually. -- Ville Syrjälä [EMAIL PROTECTED] http://www.sci.fi/~syrjala/ ------------------------------------------------------- SF.Net is sponsored by: Speed Start Your Linux Apps Now. Build and deploy apps & Web services for Linux with a free DVD software kit from IBM. Click Now! http://ads.osdn.com/?ad_id56&alloc_id438&op=click -- _______________________________________________ Dri-devel mailing list [EMAIL PROTECTED] https://lists.sourceforge.net/lists/listinfo/dri-devel
