ref: fc0f08c65112e50a75d77042d8249b6bd15a3b76
parent: 658c994cfff444e0d473dbd312638c4f609fcc81
author: cinap_lenrek <cinap_lenrek@felloff.net>
date: Fri Dec 11 10:23:03 EST 2020
pc, pc64: make sure write combining is supported in MTRR's before setting it
--- a/sys/src/9/pc/mtrr.c
+++ b/sys/src/9/pc/mtrr.c
@@ -678,6 +678,10 @@
if((new.type = str2type(tstr)) < 0)
return "bad cache type";
+ if(new.type == Writecomb
+ && (cpu0state.cap & Capwc) == 0)
+ return "write combining not supported";
+
qlock(&mtrrlk);
newstate = cpu0state;
nr = getranges(&newstate, ranges, Nranges, &new);