[PATCH 1/1] virtio-ccw: clarifications

- further qualify bit numbering
- specify summary indicator contents
- drop early printk spec; it is only a hack that was never used upstream

Reported-by: Thomas Huth <>
Signed-off-by: Cornelia Huck <>
---
 content.tex |   10 +++-------
 1 file changed, 3 insertions(+), 7 deletions(-)

diff --git a/content.tex b/content.tex
index 803615d..0a94c07 100644
--- a/content.tex
+++ b/content.tex
@@ -2174,7 +2174,8 @@ summary_indicator contains the guest address of the 8 bit summary
 indicator.
 indicator contains the guest address of an area wherin the indicators
 for the devices are contained, starting at bit_nr, one bit per
-virtqueue of the device. Bit numbers start at the left.
+virtqueue of the device. Bit numbers start at the left, i.e. the most
+significant bit in the first byte is assigned the bit number 0.
 isc contains the I/O interruption subclass to be used for the adapter
 I/O interrupt. It may be different from the isc used by the proxy
 virtio-ccw device's subchannel.
@@ -2224,7 +2225,7 @@ host->guest notification about virtqueue activity.
 
 For notifying the driver of virtqueue buffers, the device sets the
 bit in the guest-provided indicator area at the corresponding offset.
-The guest-provided summary indicator is also set. An adapter I/O
+The guest-provided summary indicator is set to 0x01. An adapter I/O
 interrupt for the corresponding interruption subclass is generated.
 The device SHOULD only generate an adapter I/O interrupt if the
 summary indicator had not been set prior to notification. The driver
@@ -2273,11 +2274,6 @@ should be passed in GPR4 for the next notification:
                                  info->cookie);
 \end{lstlisting}
 
-\subsubsection{Early printk for Virtio Consoles}\label{sec:Virtio Transport Options / Virtio over channel I/O / Device Operation / Early printk for Virtio Consoles}
-
-For the early printk mechanism, diagnose 0x500 with subcode 0 is
-used.
-
 \subsubsection{Resetting Devices}\label{sec:Virtio Transport Options / Virtio over channel I/O / Device Operation / Resetting Devices}
 
 In order to reset a device, a driver sends the
-- 
1.7.9.5