| Message ID | 20130109220122.GA12016@redhat.com |
|---|---|
| State | New |
| Headers | show |
On Thu, Jan 10, 2013 at 12:01:22AM +0200, Michael S. Tsirkin wrote: > Add code comment to clarify the reason we set ICS with ICR: > the reason was previously undocumented and git > log (commit b1332393cdd7d023de8f1f8aa136ee7866a18968) > confused rather than clarified the comments. > Digging in the mailing list archives gives the real reason > https://lists.gnu.org/archive/html/qemu-devel/2009-06/msg00401.html > > Add code comment with an explanation supplied by Bill Paul. > > Signed-off-by: Michael S. Tsirkin <mst@redhat.com> > --- > hw/e1000.c | 11 +++++++++++ > 1 file changed, 11 insertions(+) Thanks, applied to the net tree: https://github.com/stefanha/qemu/commits/net Stefan
On Thu, Jan 10, 2013 at 09:26:47AM +0100, Stefan Hajnoczi wrote: > On Thu, Jan 10, 2013 at 12:01:22AM +0200, Michael S. Tsirkin wrote: > > Add code comment to clarify the reason we set ICS with ICR: > > the reason was previously undocumented and git > > log (commit b1332393cdd7d023de8f1f8aa136ee7866a18968) > > confused rather than clarified the comments. > > Digging in the mailing list archives gives the real reason > > https://lists.gnu.org/archive/html/qemu-devel/2009-06/msg00401.html > > > > Add code comment with an explanation supplied by Bill Paul. > > > > Signed-off-by: Michael S. Tsirkin <mst@redhat.com> > > --- > > hw/e1000.c | 11 +++++++++++ > > 1 file changed, 11 insertions(+) > > Thanks, applied to the net tree: > https://github.com/stefanha/qemu/commits/net > > Stefan Actually I'm going to send v2 with a minor tweak.
On Thu, Jan 10, 2013 at 12:17:14PM +0200, Michael S. Tsirkin wrote: > On Thu, Jan 10, 2013 at 09:26:47AM +0100, Stefan Hajnoczi wrote: > > On Thu, Jan 10, 2013 at 12:01:22AM +0200, Michael S. Tsirkin wrote: > > > Add code comment to clarify the reason we set ICS with ICR: > > > the reason was previously undocumented and git > > > log (commit b1332393cdd7d023de8f1f8aa136ee7866a18968) > > > confused rather than clarified the comments. > > > Digging in the mailing list archives gives the real reason > > > https://lists.gnu.org/archive/html/qemu-devel/2009-06/msg00401.html > > > > > > Add code comment with an explanation supplied by Bill Paul. > > > > > > Signed-off-by: Michael S. Tsirkin <mst@redhat.com> > > > --- > > > hw/e1000.c | 11 +++++++++++ > > > 1 file changed, 11 insertions(+) > > > > Thanks, applied to the net tree: > > https://github.com/stefanha/qemu/commits/net > > > > Stefan > > Actually I'm going to send v2 with a minor tweak. No problem. I will wait with the next net pull request until v2 has been merged. Stefan
diff --git a/hw/e1000.c b/hw/e1000.c index 92fb00a..73e360e 100644 --- a/hw/e1000.c +++ b/hw/e1000.c @@ -230,7 +230,18 @@ set_interrupt_cause(E1000State *s, int index, uint32_t val) val |= E1000_ICR_INT_ASSERTED; } s->mac_reg[ICR] = val; + + /* + * Make sure ICR and ICS registers have the same value. + * The spec says that the ICS register is write-only. However in practice, + * on real hardware ICS is readable, and for reads it has the same value as + * ICR (except that ICS does not have the clear on read behaviour of ICR). + * + * The VxWorks PRO/1000 driver relies on this behaviour, so we have to + * emulate it. + */ s->mac_reg[ICS] = val; + qemu_set_irq(s->dev.irq[0], (s->mac_reg[IMS] & s->mac_reg[ICR]) != 0); }
Add code comment to clarify the reason we set ICS with ICR: the reason was previously undocumented and git log (commit b1332393cdd7d023de8f1f8aa136ee7866a18968) confused rather than clarified the comments. Digging in the mailing list archives gives the real reason https://lists.gnu.org/archive/html/qemu-devel/2009-06/msg00401.html Add code comment with an explanation supplied by Bill Paul. Signed-off-by: Michael S. Tsirkin <mst@redhat.com> --- hw/e1000.c | 11 +++++++++++ 1 file changed, 11 insertions(+)