diff options
Diffstat (limited to 'sys/arch/loongson')
| -rw-r--r-- | sys/arch/loongson/dev/bonito.c | 15 |
1 files changed, 9 insertions, 6 deletions
diff --git a/sys/arch/loongson/dev/bonito.c b/sys/arch/loongson/dev/bonito.c index 6762eec2025..9e141c78cc5 100644 --- a/sys/arch/loongson/dev/bonito.c +++ b/sys/arch/loongson/dev/bonito.c @@ -1,4 +1,4 @@ -/* $OpenBSD: bonito.c,v 1.10 2010/02/12 08:14:02 miod Exp $ */ +/* $OpenBSD: bonito.c,v 1.11 2010/02/24 22:33:20 miod Exp $ */ /* $NetBSD: bonito_mainbus.c,v 1.11 2008/04/28 20:23:10 martin Exp $ */ /* $NetBSD: bonito_pci.c,v 1.5 2008/04/28 20:23:28 martin Exp $ */ @@ -289,11 +289,14 @@ bonito_attach(struct device *parent, struct device *self, void *aux) if (!sc->sc_compatible) { /* - * According to Linux, changing the value of this - * undocumented register ``avoids deadlock of PCI - * reading/writing lock operation''. - * Is this really necessary, and if so, does it - * matter on other designs? + * According to Linux, changing the value of this register + * ``avoids deadlock of PCI reading/writing lock operation''. + * + * Unfortunately, documentation for the Implementation + * Specific Registers (ISR40 to ISR5C) is only found in the + * chinese version of the Loongson 2F documentation. + * + * The particular bit we set here is ``mas_read_defer''. */ /* c2000001 -> d2000001 */ REGVAL(BONITO_PCI_REG(0x4c)) |= 0x10000000; |