Johannes Berg wrote: >> It appears that I have found either a hardware error with my copy of that >> card, or there is an error >> in the ucode13 firmware. > > FWIW, the firmware is hardly involved in DMA so that's extremely > unlikely.
Does this mean the DMA engines are implemented in silicon? If so, there may be an error in the chip design. AFAIK, all Windows DMA is done to really low-order memory, and such a defect would not show there. I do not know if this card is ever used on a Mac. >> Between 2.6.24-rc2 and -rc3, code that resulted in the Descriptor Address >> Rings having low addresses was removed. At that point, my card failed with a >> DMA error. When the >> ring buffer is forced to a low address by requesting it with the GFP_DMA >> flag, then the card works. >> Note that the data buffers for DMA are still at high addresses - only the >> ring buffer is low. > > Maybe the card can't handle high addresses for the buffers or we're > doing something wrong with the address (extension) here? According to the specs, a flat 64-bit address is used for the ring buffer and it should be OK to put the buffer anywhere in RAM. Only the data buffers require messing with an extension field; however, my test machine has only 1.5 GB RAM, and all addresses fit in the low-order 32 bits. Larry _______________________________________________ Bcm43xx-dev mailing list [email protected] https://lists.berlios.de/mailman/listinfo/bcm43xx-dev
