On 5/25/05, Vladimir Dergachev <[EMAIL PROTECTED]> wrote: > No - because then the read pointer would be stationary. The CP engine > should not submit commands until the 3d engine busy is 0. (but it reacts > faster than we can catch this). > > My interpretation was that CP engine just keeps submitting the same > command to 3d engine, without fetching it and just increases the read > pointer all the time. > > It might help to dump not only read pointer but also the register showing > the last command executed. > > > > >> One way to try to make sure this does not happen is to put code in the DRM > >> driver to control the active size of the ring buffer. > > > > That could be useful for debugging, but that's about it. The thing is, we > > *want* to have the ring buffer full. If we didn't want that, we could just > > make the ring buffer smaller. But that doesn't really *solve* the problem > > either because even very small commands can take an insane amount of time > > to finish. > > I am thinking that there might be a bug where CP engine does something > funny when the ring buffer is completely full. Maybe we need to keep a > small chunk of space open so that start and end pointers are different. > > > > > In any case, it would be interesting to know how fast the RPTR still moves > > and if it becomes unstuck at some point. You also need to watch out for > > when the X server finally decides to reset the CP. I believe there's a bug > > where the X server waits much longer than intended to do this, but the > > reset could still mess with results if you're waiting for too long. > > Yep. >
IIRC RTPTR change slowly, after one minute, or something like that, of spinning around wait for the 3d engine to end there is a substantial increase in RTPTR. I haven't access to my log where i am right now. I will try to let a small empty space (maybe feeded with nop) at the end of ring buffer. Jerome Glisse ------------------------------------------------------- SF.Net email is sponsored by: GoToMeeting - the easiest way to collaborate online with coworkers and clients while avoiding the high cost of travel and communications. There is no equipment to buy and you can meet as often as you want. Try it free.http://ads.osdn.com/?ad_idt02&alloc_id135&op=click -- _______________________________________________ Dri-devel mailing list Dri-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/dri-devel
