[PATCH V2 2/3] Documentation: virtio: Add emergency write (emerg_wr) config register in virtio console.
Pranavkumar Sawargaonkar
pranavkumar at linaro.org
Mon May 6 08:19:50 EDT 2013
Signed-off-by: Pranavkumar Sawargaonkar <pranavkumar at linaro.org>
Signed-off-by: Anup Patel <anup.patel at linaro.org>
---
Documentation/virtual/virtio-spec.txt | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/Documentation/virtual/virtio-spec.txt b/Documentation/virtual/virtio-spec.txt
index 0d6ec85..3ca38f8 100644
--- a/Documentation/virtual/virtio-spec.txt
+++ b/Documentation/virtual/virtio-spec.txt
@@ -1927,11 +1927,16 @@ Ports 2 onwards only if VIRTIO_CONSOLE_F_MULTIPORT is set
ports; configuration fields nr_ports and max_nr_ports are
valid and control virtqueues will be used.
+ VIRTIO_CONSOLE_F_EMERG_WRITE(2) Device has support for emergency
+ write. Configuration filed emerg_wr is valid.
+
Device configuration layout The size of the console is supplied
in the configuration space if the VIRTIO_CONSOLE_F_SIZE feature
is set. Furthermore, if the VIRTIO_CONSOLE_F_MULTIPORT feature
is set, the maximum number of ports supported by the device can
- be fetched.struct virtio_console_config {
+ be fetched. If VIRTIO_CONSOLE_F_EMERG_WRITE is set then one can
+ use emergency write to output single character without initializing
+ virtio queues. struct virtio_console_config {
u16 cols;
@@ -1941,6 +1946,7 @@ Ports 2 onwards only if VIRTIO_CONSOLE_F_MULTIPORT is set
u32 max_nr_ports;
+ u32 emerg_wr;
};
Device Initialization
--
1.7.9.5
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