On Fri, Sep 05, 2014 at 08:53:01PM +0000, KY Srinivasan wrote: > > > > -----Original Message----- > > From: Greg KH [mailto:gregkh@xxxxxxxxxxxxxxxxxxx] > > Sent: Friday, September 5, 2014 12:12 PM > > To: KY Srinivasan > > Cc: linux-kernel@xxxxxxxxxxxxxxx; devel@xxxxxxxxxxxxxxxxxxxxxx; > > olaf@xxxxxxxxx; apw@xxxxxxxxxxxxx; jasowang@xxxxxxxxxx > > Subject: Re: [PATCH 1/1] Drivers: hv: vmbus: Enable interrupt driven flow > > control > > > > On Fri, Sep 05, 2014 at 11:23:22AM -0700, K. Y. Srinivasan wrote: > > > This is a win8 feature that has been implemented. Turn on the feature > > > bit to enable the feature. > > > > What does those two sentances even mean? > Greg, > > The feature has been implemented and has been in the tree for a while. What feature? What is "This" in the first sentance? > However, the feature was not advertised to the host and this patch does just that. > > > > > With this feature turned on, > > > > What is "this"? > "this" refers to the feature bit. > > > > > when the host is waiting > > > for space to become available on the ringbuffer (host to guest), the > > > guest will interrupt the host when space becomes available (as part of > > > draining the ring buffer). > > > > > > Signed-off-by: K. Y. Srinivasan <kys@xxxxxxxxxxxxx> > > > --- > > > drivers/hv/ring_buffer.c | 5 +++++ > > > 1 files changed, 5 insertions(+), 0 deletions(-) > > > > > > diff --git a/drivers/hv/ring_buffer.c b/drivers/hv/ring_buffer.c index > > > 15db66b..6361d12 100644 > > > --- a/drivers/hv/ring_buffer.c > > > +++ b/drivers/hv/ring_buffer.c > > > @@ -361,6 +361,11 @@ int hv_ringbuffer_init(struct hv_ring_buffer_info > > *ring_info, > > > ring_info->ring_buffer->read_index = > > > ring_info->ring_buffer->write_index = 0; > > > > > > + /* > > > + * Set the feature bit for enabling flow control. > > > + */ > > > + ring_info->ring_buffer->feature_bits.value = 1; > > > > What happens if you are running on an old system that doesn't support this > > new "feature"? > The control structure for the ring buffer (where this feature bit is) has not changed and so, for > hosts that don't understand this, it does not matter. > > Hope this helps. Let me know if you want me to rewrite comment and resend this patch. Please do, it's confusing :) thanks, greg k-h _______________________________________________ devel mailing list devel@xxxxxxxxxxxxxxxxxxxxxx http://driverdev.linuxdriverproject.org/mailman/listinfo/driverdev-devel
