CVS commit: src/sys/arch/alpha/pci

["Jason R Thorpe" <thorpej%netbsd.org@localhost>]

Module Name:    src
Committed By:   thorpej
Date:           Sat Jul 17 00:30:39 UTC 2021

Modified Files:
        src/sys/arch/alpha/pci: cia_dma.c ciavar.h

Log Message:
Back in rev 1.21, mhitch@ fixed an issue with his 1.5GB RAM PWS 500au
by using a fall-back to the ISA DMA window if DMA was out of range for
the 1G @ 1G PCI DMA window.  Alas, the ISA DMA window is pretty small
(8M @ 8M), and it's possible to starve it with PCI devices that might
have, for example, large control data structures there.

So, instead, if the system has more than 1G of RAM, use Window 3
(previously unused) as a SGMAP window 1G @ 3G, and set that as the
fall-back if the direct-mapped window fails.


To generate a diff of this commit:
cvs rdiff -u -r1.34 -r1.35 src/sys/arch/alpha/pci/cia_dma.c
cvs rdiff -u -r1.20 -r1.21 src/sys/arch/alpha/pci/ciavar.h

Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.