Michel Dänzer wrote: > On Fre, 2002-09-27 at 16:47, Keith Whitwell wrote: > >>Michel Dänzer wrote: >> >>>On Don, 2002-09-26 at 18:17, Keith Whitwell wrote: >>> >>> >>>>Michel Dänzer wrote: >>>> >>>> >>>>>Something else I've been thinking about is that relying on the >>>>>swi_emitted and swi_received counters being in sync is pretty fragile. >>>>>It might be better to use a scratch register instead. >>>>> >>>>> >>>>Yes, it could be made more robust. >>>> >>>> >>>Do you think the approach with a scratch register is good? >>> >>Yep, but I guess you have to worry about then going to sleep *after* the >>interrupt has arrived, if there is a delay in getting the scratch write across >>the bus, compared to the irq, which should be instantaneous. >> > > Is that really an issue? The scratch register is written to before the > interrupt is triggered, so I'd expect a register read to yield the > correct value when the interrupt has arrived.
I was under the understanding that the scratch registers were actually 'shadows' in main memory, updated by the card across the agp bus. If so, I don't think there's any guarantee of synchronization with the irq delivery. Maybe it's not a real risk, but certainly worthwhile to keep it in mind. > > >>... >> >> >>>>We shoudl add diagnostics to the -EBUSY case in wait_irq to try and figure out >>>>what has happened -- particularly have the interrupts been disabled? >>>> >>>> >>>Turns out they haven't. GEN_INT_CNTL looks exactly like it should. >>>Interestingly, the GEN_INT_STATUS bits are set as well, and >>>acknowledging them helps. So it seems that somehow, the service routine >>>didn't get called for an interrupt, or the acknowledgement got lost. >>> >>>If the updated patch works for you as well, I'll commit it. >>> >>The patch doesn't seem to do anything about this case, just print something out... >> > > Are we talking about the same patch, > http://penguinppc.org/~daenzer/DRI/radeon-swi-scratch.diff with md5sum > 6abf27a2a1d6a4e57a8c36b19ef0e17b? It worked fine for nicod yesterday... > (BTW it would have been a pain in the neck for him to debug this without > reinit) OK, I see it now. It's a big hack to be doing this. I'd really like to know why this happens, but in the mean time I'm ok to see it go in. Maybe I should be more pedantic about things... Keith ------------------------------------------------------- This sf.net email is sponsored by:ThinkGeek Welcome to geek heaven. http://thinkgeek.com/sf _______________________________________________ Dri-devel mailing list [EMAIL PROTECTED] https://lists.sourceforge.net/lists/listinfo/dri-devel
