On Mon, Sep 29, 2008 at 11:22:36PM +1000, Finn Thain wrote: > On Sun, 28 Sep 2008, Brad Boyer wrote: > > > The Guide to Mac Family Hardware says that IRQ and DRQ are connected > > > to the OSS. AFAICT, DRQ is wired to VIA2 CA2 on all machines that have > > > VIA2/RBV. > > > > The Guide also says that the PCR bits 1-3 on VIA2 are related to DRQ. Do > > we know if we're setting the right values there? > > Well, that is partly why I tested the Mac II, PB 150 and PB 190. On the PB > 150 (RBV) there is no PCR. But on the Mac II we have all of the relevant > schematics and data, so I'm certain that we've set that correctly. The PB > 190 has a "quadra-style" VIA, so it is most likely set correctly there too > (or so I like to think! Macsbug says PCR is 0 on both Mac II and PB 190 > which make no sense to me.) It's possible that macsbug isn't generating the right size load request to make the chip happy. The 6522 is really just an 8 bit chip, and I think the address decoder gets unhappy if you do a 16 or 32 bit load/store. The PCR bits definitely look right in the code for the old II series models, and supposedly the RBV systems just do the right thing. The problem is that the "quadra-style" VIA emulation isn't all the same in every model. They used a new ASIC almost every time. It's probably right, but I don't know. > >... > > The odd thing about the DRQ on the IIfx going to OSS is that the list in > > mac_oss.h has defines for all 16 interrupt bits, and there's only one > > for SCSI. My understanding is that the list was based on the A/UX > > headers from Apple and should be accurate. I never tried to request one > > of the IRQs in the set that we don't have claimed by any driver to see > > if one of them really is the DRQ. > > I just checked the oss.h A/UX header file and it agrees with mac_oss.h. > But perhaps DRQ was unused by A/UX (although the SCSI DMA chip would have > needed it)? That might explain why oss.h lists 3 unused IRQs. Or perhaps > DRQ and IRQ lines from the NCR5380 core share the same OSS IRQ. Well, that was the original source so it better agree. If they really are wired to the same IRQ line on OSS, it should have worked. The interrupt routine appeared to be checking the right status bits in the 5380 to check for all the appropriate condition flags. It appeared that it just wasn't getting called. Maybe I'll find some time and just try each of the three unused interrupts and see if they do something. I would have thought that using DMA without the DRQ would be pointless. Brad Boyer flar@xxxxxxxxxxxxx -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
